NAU8812
emPowerAudio
™
Datasheet Revision 2.0 Page 1 of 109 January 2011
Mono Audio Codec with Speaker Driver
emPowerAudio
™
1. GENERAL DESCRIPTION
The NAU8812 is a cost effective and low power wideband MONO audio CODEC. It is designed for voice telephony
related applications. Functions include Automatic Level Control (ALC) with noise gate, PGA, standard audio interface
I2S, PCM with time slot assignment, and on-chip PLL. The device provides one differential microphone input and one
single ended auxiliary input (multi purpose). There are few variable gain control stages in the audio path. It also
includes MONO line output and integrated BTL speaker driver.
The analog inputs have PGA on the front end, allowing dynamic range optimization with a wide range of input
sources. The microphone amplifiers have a programmable gain from -12dB to +35.25dB to handle both amplified
microphones. In addition to a digital high pass filter to remove DC offset voltages, the ADC also features voice band
digital filtering. Voice-band data is accepted by the audio interface (I2S). The DAC converter path includes filtering
and mixing, programmable-gain amplifiers (PGA), and soft muting. The digital interfaces, 2-Wire or SPI, have
independent supply voltage to allow integration into multiple supply systems. The NAU8812 operates at supply
voltages from 2.5V to 3.6V, although the digital core can operate at voltage as low as 1.71V to save power.
2. FEATURES
24-bit signal processing linear Audio CODEC
Audio DAC: 93dB SNR and -84dB THD
Audio ADC: 91dB SNR and -79dB THD
Support variable sample rates from 8 - 48kHz
Integrated BTL Speaker Driver 800mW (8Ω / 5V)
Integrated Headset Driver 40mW (16Ω / 3.3V)
Analog I/O
Integrated programmable Microphone Amplifier
Integrated Line Input and Line Output
Earphone / Speaker / Line Output selection
Microphone / Line Inputs selection
Low Noise bias supplied for microphone
On-chip PLL
Interfaces
I2S digital interface PCM time slot assignment
SPI & 2-Wire serial control Interface (I2C style;
Read/Write capable)
Low Power, Low Voltage
Analog Supply: 2.5V to 3.6V
Digital Supply: 1.71V to 3.6V
Nominal Operating Voltage: 3.3V
Additional features
Programmable ALC
ADC Notch Filter
Programmable High Pass Filter
Digital A/D-D/A Passthrough
AEC-Q100 & TS16949 qualification
Industrial temperature: range: –40C to +85C
Applications
VoIP Telephones]
Conference speaker-phone
IP PBX
Mobile Telephone Hands-free Kits
Residential & Consumer Intercoms
Digital Audio Interface Serial Control Interface
Line Driver
BTL
Speaker
Driver
Microphone
Interface
Output
Mixers
&
Speaker
Volume
ADC DAC
Micophone
Bias
-1
Input
Mixers
&
Gain
Stage
I2S PCM 2-wire SPI
AUX
MIC-
MIC+
MICBIAS
Digital I/OAudio I/O
AUX
SPK+
SPK-
CSb/GPIO
ADC Filter
Volume
Control
HPF
Notch Filter
DAC Filter
Volume
Control
Limiter
PLL
GPIO
NAU8812
emPowerAudio
™
Datasheet Revision 2.0 Page 2 of 109 January 2011
3. PIN CONFIGURATION
Figure 1: 28-Pin SSOP Package
Figure 2: 32-Pin QFN Package
CSb/GPIO
VREF
MIC -
MIC +
MICBIAS
NC
VDDA
VSSA
VSSA
VDDC
VDDB
VSSD
ADCOUT
DACIN
FS
AUX
VDDSPK
VDDSPK
SPKOUT -
VSSSPK
VSSSPK
SPKOUT +
MOUT
MODE
SDIO
SCLK
BCLK
MCLK
2
3
4
5
6
7
8
1
10
11
12
13
14
9
27
26
25
24
23
22
21
28
19
18
17
16
15
20
NAU8812
MONO AUDIO
CODEC
SSOP 28-Pin
SPKOUT -
BCLK
MCLK
MICBIAS
NC
VSSA
VDDL
SPKOUT +
MOUT
SDIO
NC
SO
MIC -
MIC +
AUX
SCLK
ADCOUT
DACIN
FS
MODE
VDDA
VSSA
VDDC
VDDB
VSSD
VSSSPK
VSSSPK
VSSD
CSb/GPIO VDDSPK
VDDSPK
VREF
2
3
4
5
6
7
8
1
10
11
12
13
14
15
16
9
31
30
29
28
27
26
25
32
23
22
21
20
19
18
17
24
NAU8812
MONO AUDIO
CODEC
QFN 32-Pin
NAU8812
emPowerAudio
™
Datasheet Revision 2.0 Page 3 of 109 January 2011
4. PIN DESCRIPTION
Pin Name
28-Pin
32-Pin
Functionality
A/D
Pin Type
VREF
1
29
Decoupling internal analog mid supply reference
voltage
A
O
MIC-
2
30
Microphone Negative Input
A
I
MIC+
3
31
Microphone Positive Input
A
I
MICBIAS
4
32
Microphone Bias
A
O
NC
5
1
No Connect
VDDA
6
2
Analog Supply
A
I
VSSA
7
3
Analog Ground
A
O
VSSA
8
4
Analog Ground
A
O
VDDL
-
5
Logic supply voltage. This pin should not be
connected up to an external supply
D
O
VDDC
9
6
Digital Supply Core
D
I
VDDB
10
7
Digital Supply Buffer
D
I
VSSD
11
8
Digital Ground
D
O
VSSD
-
9
Digital Ground
D
O
ADCOUT
12
10
Digital Audio Data Output
D
O
DACIN
13
11
Digital Audio Data Input
D
I
FS
14
12
Frame Sync
D
I/O
BCLK
15
13
Bit Clock
D
I/O
MCLK
16
14
Master Clock
D
I
CSb/GPIO
17
15
SPI Chip Select or General Purposes 1 I/O
D
I/O
SCLK
18
16
SPI or 2-Wire Serial Clock
D
I
SDIO
19
17
SPI Data In or 2-Wire I/O
D
O
SO
-
18
SPI Data Output
D
O
MODE
20
19
Interface Select (2-Wire or SPI)
D
I
NC
-
20
No Connect
MOUT
21
21
MONO Output
A
O
SPKOUT+
22
22
Speaker Positive Output
A
O
VSSSPK
23
23
Speaker Ground
A
O
VSSSPK
24
24
Speaker Ground
A
O
SPKOUT-
25
25
Speaker Negative Output
A
O
VDDSPK
26
26
Speaker Supply
A
I
VDDSPK
27
27
Speaker Supply
A
I
AUX
28
28
Auxiliary Input
A
I
Table 1: Pin Description for SSOP and QFN Packages
Notes
1. The 32-QFN package includes a bulk ground connection pad on the underside of the chip. This bulk ground
should be thermally tied to the PCB, and electrically tied to the analog ground.
2. Unused analog input pins should be left as no-connection.
3. Under all condition when digital pins are not used they should be tied to ground.
4. Pins designated as NC (Not Internally Connected) should be left as no-connection
NAU8812
emPowerAudio
™
Datasheet Revision 2.0 Page 4 of 109 January 2011
5. BLOCK DIAGRAM
Figure 3: NAU8812 General Block Diagram
R
R
HPF
ALC
NOTCH
FILTER
LIMITER
MIC+
MIC-
MOUT
SPKOUT+
SPKOUT-
AUX BYPASS
MOUTMXEN[3]
(0x03)
SPKGAIN[5:0]
(0x36)
DACEN[0]
(0x03)
DACSPK[0]
(0X32)
AUXMOUT[2]
(0x38)
(Sidetone) BYPASS
AUXPGA[2]
(0x2C)
NMICPGA[1]
(0x2C)
PMICPGA
ADC DAC
AUX
20k
20k
VREF
MICBIAS
VDDA
VREF
VSSA
VDDB
VSSD
VDDSPK
VDDSPK
VSSSPK
VSSSPK
VREF
AUXM[3]
(0x2C) AUXEN[6]
(0x01)
PLL
MCLK
CONTROL
INTERFACE
BCLK
DACIN
ADCOUT
FS
DIGITAL AUDIO
INTERFACE
MODE
SCLK
SDIO
CSb/GPIO
PLLEN[5]
(0x01)
SO
VSSA
NC
VDDC
DACMOUT[0]
(0x38)
SPKMXEN[2]
(0x03)
AUXSPK[5]
(0x32)
BYPMOUT[1]
(0x38)
BYPSPK[1]
(0x32)
SPK3V[2]
(0x31)
MOUT3V[3]
(0x31)
AUXBSTGAIN[2:0]
(0x2F) = 000
PMICBSTGAIN[6:4]
(0x2F) = 000
PGAMT[6]
(0x2D) PMICBSTGAIN[6:4]
(0x2F)
PGABST[8]
(0x2F)
AUXBSTGAIN[2:0]
(0x2F)
BSTEN[4]
(0x02)
PGAGAIN
(0x2D)
-12 dB to
+35.25 dB
PGAEN[2]
(0x02)
Σ
Σ
Σ
MICROPHONE
BIAS
VDDA
ADCEN[0]
(0x02)
MICBIASEN[4]
(0x2F)
1.0X
1.5X
1.0X
1.5X
1.0X
1.5X
AUXM[3]
(0x2C)
NAU8812
emPowerAudio
™
Datasheet Revision 2.0 Page 5 of 109 January 2011
6. Table of Contents
1. GENERAL DESCRIPTION .................................................................................................................................. 1
2. FEATURES ......................................................................................................................................................... 1
3. PIN CONFIGURATION ....................................................................................................................................... 2
4. PIN DESCRIPTION ............................................................................................................................................. 3
5. BLOCK DIAGRAM .............................................................................................................................................. 4
6. TABLE OF CONTENTS ...................................................................................................................................... 5
7. LIST OF FIGURES .............................................................................................................................................. 9
8. LIST OF TABLES .............................................................................................................................................. 11
9. ABSOLUTE MAXIMUM RATINGS .................................................................................................................... 12
10. OPERATING CONDITIONS .............................................................................................................................. 12
11. ELECTRICAL CHARACTERISTICS ................................................................................................................. 13
12. FUNCTIONAL DESCRIPTION .......................................................................................................................... 16
12.1. INPUT PATH .............................................................................................................................................. 16
12.1.1. The Single Ended Auxiliary Input (AUX) ............................................................................................. 16
12.1.2. The differential microphone input (MIC- & MIC+ pins) ........................................................................ 18
12.1.2.1. Positive Microphone Input (MIC+)............................................................................................... 19
12.1.2.2. Negative Microphone Input (MIC-) .............................................................................................. 19
12.1.2.3. PGA Gain Control ....................................................................................................................... 20
12.1.3. PGA Boost Stage ................................................................................................................................ 20
12.2. MICROPHONE BIASING ........................................................................................................................... 22
12.3. ADC DIGITAL FILTER BLOCK .................................................................................................................. 24
12.3.1. Programmable High Pass Filter (HPF) ................................................................................................ 25
12.3.2. Programmable Notch Filter (NF) ......................................................................................................... 25
12.3.3. Digital ADC Gain Control .................................................................................................................... 26
12.4. PROGRAMMABLE GAIN AMPLIFIER (PGA) ............................................................................................ 26
12.4.1. Automatic level control (ALC) .............................................................................................................. 26
12.4.1.1. Normal Mode .............................................................................................................................. 29
12.4.1.2. ALC Hold Time (Normal mode Only) .......................................................................................... 29
12.4.2. Peak Limiter Mode .............................................................................................................................. 30
12.4.3. Attack Time ......................................................................................................................................... 31
12.4.4. Decay Times ....................................................................................................................................... 31
12.4.5. Noise gate (normal mode only) ........................................................................................................... 31
12.4.6. Zero Crossing...................................................................................................................................... 32
12.5. DAC DIGITAL FILTER BLOCK .................................................................................................................. 33
12.5.4. Hi-Fi DAC De-Emphasis and Gain Control ......................................................................................... 34
12.5.5. Digital DAC Output Peak Limiter ......................................................................................................... 35
12.5.6. Volume Boost ...................................................................................................................................... 35
12.6. ANALOG OUTPUTS .................................................................................................................................. 36
12.6.1. Speaker Mixer Outputs ....................................................................................................................... 36
12.6.2. MONO Mixer Output ........................................................................................................................... 37
12.6.3. Unused Analog I/O .............................................................................................................................. 38
12.7. GENERAL PURPOSE I/O .......................................................................................................................... 39
12.7.1. Slow Timer Clock ................................................................................................................................ 40
NAU8812
emPowerAudio
™
Datasheet Revision 2.0 Page 6 of 109 January 2011
12.7.2. Jack Detect ......................................................................................................................................... 40
12.7.3. Thermal Shutdown .............................................................................................................................. 41
12.8. CLOCK GENERATION BLOCK ................................................................................................................. 42
12.9. CONTROL INTERFACE ............................................................................................................................ 46
12.9.1. SPI Serial Control ................................................................................................................................ 46
12.9.1.1. 16-bit Write Operation (default) ................................................................................................... 47
12.9.1.2. 24-bit Write Operation ................................................................................................................. 47
12.9.1.3. 32-bit Read Operation ................................................................................................................ 48
12.9.2. 2-WIRE Serial Control Mode (I2C Style Interface) ............................................................................... 48
12.9.2.1. 2-WIRE Protocol Convention ...................................................................................................... 49
12.9.2.2. 2-WIRE Write Operation ............................................................................................................. 49
12.9.2.3. 2-WIRE Read Operation ............................................................................................................. 50
12.10. DIGITAL AUDIO INTERFACES ................................................................................................................. 51
12.10.1. Right Justified audio data .................................................................................................................... 52
12.10.2. Left Justified audio data ...................................................................................................................... 53
12.10.3. I2S audio data ...................................................................................................................................... 54
12.10.4. PCM audio data .................................................................................................................................. 55
12.10.5. PCM Time Slot audio data .................................................................................................................. 56
12.10.6. Companding ........................................................................................................................................ 57
12.11. POWER SUPPLY....................................................................................................................................... 58
12.11.1. Power-On Reset .................................................................................................................................. 58
12.11.2. Power Related Software Considerations ............................................................................................. 58
12.11.3. Software Reset.................................................................................................................................... 59
12.11.4. Power Up/Down Sequencing .............................................................................................................. 59
12.11.5. Reference Impedance (REFIMP) and Analog Bias ............................................................................. 60
12.11.6. Power Saving ...................................................................................................................................... 60
12.11.7. Estimated Supply Currents ................................................................................................................. 61
13. REGISTER DESCRIPTION ............................................................................................................................... 62
13.1. SOFTWARE RESET .................................................................................................................................. 64
13.2. POWER MANAGEMENT REGISTERS ..................................................................................................... 64
13.2.1. Power Management 1 ......................................................................................................................... 64
13.2.2. Power Management 2 ......................................................................................................................... 65
13.2.3. Power Management 3 ......................................................................................................................... 65
13.3. AUDIO CONTROL REGISTERS ................................................................................................................ 65
13.3.1. Audio Interface Control ....................................................................................................................... 65
13.3.2. Audio Interface Companding Control .................................................................................................. 66
13.3.3. Clock Control Register ........................................................................................................................ 67
13.3.4. Audio Sample Rate Control Register .................................................................................................. 68
13.3.5. GPIO Control Register ........................................................................................................................ 69
13.3.6. DAC Control Register .......................................................................................................................... 69
13.3.7. DAC Gain Control Register ................................................................................................................. 70
13.3.8. ADC Control Register .......................................................................................................................... 70
13.3.9. ADC Gain Control Register ................................................................................................................. 71
13.4. DIGITAL TO ANALOG CONVERTER (DAC) LIMITER REGISTERS ........................................................ 72
13.5. NOTCH FILTER REGISTERS ................................................................................................................... 73
13.6. AUTOMATIC LEVEL CONTROL REGISTER ............................................................................................ 74
NAU8812
emPowerAudio
™
Datasheet Revision 2.0 Page 7 of 109 January 2011
13.6.1. ALC1 REGISTER ................................................................................................................................ 74
13.6.2. ALC2 REGISTER ................................................................................................................................ 75
13.6.3. ALC3 REGISTER ................................................................................................................................ 76
13.7. NOISE GAIN CONTROL REGISTER......................................................................................................... 77
13.8. PHASE LOCK LOOP (PLL) REGISTERS .................................................................................................. 78
13.8.1. PLL Control Registers ......................................................................................................................... 78
13.8.2. Phase Lock Loop Control (PLL) Registers .......................................................................................... 78
13.9. INPUT, OUTPUT, AND MIXERS CONTROL REGISTER .......................................................................... 79
13.9.1. Attenuation Control Register ............................................................................................................... 79
13.9.2. Input Signal Control Register .............................................................................................................. 79
13.9.3. PGA Gain Control Register ................................................................................................................. 80
13.9.4. ADC Boost Control Registers .............................................................................................................. 81
13.9.5. Output Register ................................................................................................................................... 81
13.9.6. Speaker Mixer Control Register .......................................................................................................... 82
13.9.7. Speaker Gain Control Register ........................................................................................................... 82
13.9.8. MONO Mixer Control Register ............................................................................................................ 83
13.9.9. Trimming Register ............................................................................................................................... 83
13.10. PCM TIME SLOT CONTROL & ADCOUT IMPEDANCE OPTION CONTROL .......................................... 84
13.10.1. PCM1 TIMESLOT CONTROL REGISTER ......................................................................................... 84
13.10.2. PCM2 TIMESLOT CONTROL REGISTER ......................................................................................... 84
13.11. REGISTER ID (READ ONLY) .................................................................................................................... 85
13.11.1. Device revision register ....................................................................................................................... 85
13.11.2. 2-WIRE ID Register (READ ONLY) ..................................................................................................... 85
13.11.3. Additional ID (READ ONLY) ................................................................................................................ 85
13.12. Reserved .................................................................................................................................................... 86
13.13. OUTPUT Driver Control Register ............................................................................................................... 86
13.14. AUTOMATIC LEVEL CONTROL ENHANCED REGISTER ....................................................................... 87
13.14.1. ALC1 Enhanced Register .................................................................................................................... 87
13.14.2. ALC Enhanced 2 Register ................................................................................................................... 87
13.15. MISC CONTROL REGISTER .................................................................................................................... 88
13.16. Output Tie-Off REGISTER ......................................................................................................................... 89
13.17. ALC PEAK-TO-PEAK READOUT REGISTER ........................................................................................... 89
13.18. ALC PEAK READOUT REGISTER ............................................................................................................ 89
13.19. AUTOMUTE CONTROL AND STATUS READ REGISTER ....................................................................... 90
13.20. Output Tie-off Direct Manual Control REGISTER ...................................................................................... 90
14. CONTROL INTERFACE TIMING DIAGRAM .................................................................................................... 91
14.1. SPI WRITE TIMING DIAGRAM .................................................................................................................. 91
14.2. SPI READ TIMING DIAGRAM ................................................................................................................... 91
14.3. 2-WIRE TIMING DIAGRAM ....................................................................................................................... 93
15. AUDIO INTERFACE TIMING DIAGRAM........................................................................................................... 94
15.1. AUDIO INTERFACE IN SLAVE MODE ...................................................................................................... 94
15.2. AUDIO INTERFACE IN MASTER MODE .................................................................................................. 94
15.3. PCM AUDIO INTERFACE IN SLAVE MODE (PCM Audo Data) ................................................................ 95
15.4. PCM AUDIO INTERFACE IN MASTER MODE (PCM Audo Data) ............................................................ 95
15.5. PCM AUDIO INTERFACE IN SLAVE MODE (PCM Time Slot Mode )....................................................... 96
15.6. PCM AUDIO INTERFACE IN MASTER MODE (PCM Time Slot Mode ) ................................................... 96
15.7. System Clock (MCLK) Timing Diagram ............................................................................................... 97
NAU8812
emPowerAudio
™
Datasheet Revision 2.0 Page 8 of 109 January 2011
15.8. µ-LAW ENCODE DECODE CHARACTERISTICS ..................................................................................... 98
15.9. A-LAW ENCODE DECODE CHARACTERISTICS..................................................................................... 99
15.10. µ-LAW / A-LAW CODES FOR ZERO AND FULL SCALE ........................................................................ 100
15.11. µ-LAW / A-LAW OUTPUT CODES (DIGITAL MW) .................................................................................. 100
16. DIGITAL FILTER CHARACTERISTICS .......................................................................................................... 101
17. TYPICAL APPLICATION ................................................................................................................................. 103
18. PACKAGE SPECIFICATION ........................................................................................................................... 105
18.1. 28 Pin SSOP32-Pin QFN ......................................................................................................................... 105
18.1. 32-Pin QFN .............................................................................................................................................. 106
19. ORDERING INFORMATION ........................................................................................................................... 107
20. VERSION HISTORY ....................................................................................................................................... 108
NAU8812
emPowerAudio
™
Datasheet Revision 2.0 Page 9 of 109 January 2011
7. List of Figures
Figure 1: 28-Pin SSOP Package ................................................................................................................................... 2
Figure 2: 32-Pin QFN Package ..................................................................................................................................... 2
Figure 3: NAU8812 General Block Diagram ................................................................................................................. 4
Figure 4: Auxiliary Input Circuit Block Diagram with AUXM[3] = 0 .............................................................................. 17
Figure 5: Auxiliary Input Circuit Block Diagram with AUXM[3] = 1 .............................................................................. 17
Figure 6: Input PGA Circuit Block Diagram ................................................................................................................. 18
Figure 7: Boost Stage Block Diagram ......................................................................................................................... 20
Figure 8: Microphone Bias Schematic ......................................................................................................................... 22
Figure 9: ADC Digital Filter Path Block Diagram ......................................................................................................... 24
Figure 10: ALC Block Diagram .................................................................................................................................... 27
Figure 11: ALC Response Graph ................................................................................................................................ 27
Figure 12: ALC Normal Mode Operation ..................................................................................................................... 29
Figure 13: ALC Hold Time ........................................................................................................................................... 30
Figure 14: ALC Limiter Mode Operations .................................................................................................................... 30
Figure 15: ALC Operation with Noise Gate disabled ................................................................................................... 31
Figure 16: ALC Operation with Noise Gate Enabled ................................................................................................... 32
Figure 17: DAC Digital Filter Path ............................................................................................................................... 33
Figure 18: DAC Digital Limiter Control ........................................................................................................................ 35
Figure 19: Speaker and MONO Analogue Outputs ..................................................................................................... 36
Figure 20: Tie-off Options for the Speaker and MONO output Pins ............................................................................ 38
Figure 21: PLL and Clock Select Circuit ...................................................................................................................... 42
Figure 22: Register write operation using a 16-bit SPI Interface ................................................................................. 47
Figure 23: Register Write operation using a 24-bit SPI Interface ................................................................................ 48
Figure 24: Register Read operation through a 32-bit SPI Interface ............................................................................ 48
Figure 25: Valid START Condition .............................................................................................................................. 49
Figure 26: Valid Acknowledge ..................................................................................................................................... 49
Figure 27: Valid STOP Condition ................................................................................................................................ 49
Figure 28: Slave Address Byte, Control Address Byte, and Data Byte ....................................................................... 49
Figure 29: Byte Write Sequence ................................................................................................................................. 50
Figure 30: 2-Wire Read Sequence .............................................................................................................................. 50
Figure 31: Right Justified Audio Interface (Normal Mode) ........................................................................................... 52
Figure 32: Right Justified Audio Interface (Special mode) .......................................................................................... 52
Figure 33: Left Justified Audio Interface (Normal Mode) ............................................................................................. 53
Figure 34: Left Justified Audio Interface (Special mode) ............................................................................................. 53
Figure 35: I2S Audio Interface (Normal Mode) ............................................................................................................ 54
Figure 36: I2S Audio Interface (Special mode)............................................................................................................ 54
NAU8812
emPowerAudio
™
Datasheet Revision 2.0 Page 10 of 109 January 2011
Figure 37: PCM Mode Audio Interface (Normal Mode) ............................................................................................... 55
Figure 38: PCM Mode Audio Interface (Special mode) ............................................................................................... 55
Figure 39: PCM Time Slot Mode (Time slot = 0) (Normal Mode) ................................................................................ 56
Figure 40: PCM Time Slot Mode (Time slot = 0) (Special mode) ................................................................................ 56
Figure 41: The Programmable ADCOUT Pin .............................................................................................................. 84
Figure 42: SPI Write Timing Diagram .......................................................................................................................... 91
Figure 43: SPI Read Timing Diagram ......................................................................................................................... 91
Figure 44: 2-Wire Timing Diagram .............................................................................................................................. 93
Figure 45: Audio Interface Slave Mode Timing Diagram ............................................................................................. 94
Figure 46: Audio Interface in Master Mode Timing Diagram ....................................................................................... 94
Figure 47: PCM Audio Interface Slave Mode Timing Diagram .................................................................................... 95
Figure 48: PCM Audio Interface Slave Mode Timing Diagram .................................................................................... 95
Figure 49: PCM Audio Interface Slave Mode (PCM Time Slot Mode )Timing Diagram .............................................. 96
Figure 50: PCM Audio Interface Master Mode (PCM Time Slot Mode )Timing Diagram ............................................. 96
Figure 51: MCLK Timing Diagram ............................................................................................................................... 97
Figure 52: DAC Filter Frequency Response ............................................................................................................. 102
Figure 53: ADC Filter Frequency Response ............................................................................................................. 102
Figure 54: DAC Filter Ripple ..................................................................................................................................... 102
Figure 55: ADC Filter Ripple ..................................................................................................................................... 102
Figure 56: Application Diagram 28-Pin SSOP ........................................................................................................... 103
Figure 57: Application Diagram for 32-Pin QFN ........................................................................................................ 104
NAU8812
emPowerAudio
™
Datasheet Revision 2.0 Page 11 of 109 January 2011
8. List of Tables
Table 1: Pin Description for SSOP and QFN Packages ................................................................................................ 3
Table 2: Register associated with Input PGA Contro .................................................................................................. 18
Table 3: Microphone Non-Inverting Input Impedances ................................................................................................. 19
Table 4: Microphone Inverting Input Impedances ....................................................................................................... 19
Table 5: Registers associated with ALC and Input PGA Gain Control ........................................................................ 20
Table 6: Registers associated with PGA Boost Stage Control .................................................................................... 21
Table 7: Register associated with Microphone Bias .................................................................................................... 22
Table 8: Microphone Bias Voltage Control .................................................................................................................. 23
Table 9: Register associated with ADC ....................................................................................................................... 24
Table 10: High Pass Filter Cut-off Frequencies (HPFAM=1) ....................................................................................... 25
Table 11: Registers associated with Notch Filter Function .......................................................................................... 25
Table 12: Equations to Calculate Notch Filter Coefficients ......................................................................................... 26
Table 13: Register associated with ADC Gain ............................................................................................................ 26
Table 14: Registers associated with ALC Control ....................................................................................................... 28
Table 15: ALC Maximum and Minimum Gain Values .................................................................................................. 28
Table 16: Registers associated with DAC Gain Control .............................................................................................. 33
Table 17: Speaker Output Controls ............................................................................................................................. 37
Table 18: MONO Output Controls ............................................................................................................................... 37
Table 19: General Purpose Control ............................................................................................................................. 40
Table 20: Jack Insert Detect mode.............................................................................................................................. 40
Table 21: Jack Insert Detect controls .......................................................................................................................... 41
Table 22: Thermal Shutdown ...................................................................................................................................... 41
Table 23: Registers associated with PLL .................................................................................................................... 43
Table 24: Registers associated with PLL .................................................................................................................... 44
Table 25: PLL Frequency Examples ........................................................................................................................... 45
Table 26: Control Interface Selection .......................................................................................................................... 46
Table 27: Standard Interface modes ........................................................................................................................... 51
Table 28: Audio Interface Control Registers ............................................................................................................... 51
Table 29: Companding Control ................................................................................................................................... 57
Table 30: Power up sequence..................................................................................................................................... 60
Table 31: Power down Sequence ............................................................................................................................... 60
Table 32: Registers associated with Power Saving..................................................................................................... 61
Table 33: VDDA 3.3V Supply Current ......................................................................................................................... 61
Table 34: SPI Timing Parameters ............................................................................................................................... 92
Table 35: 2-WireTiming Parameters ........................................................................................................................... 93
Table 36: Audio Interface Timing Parameters ............................................................................................................. 97
Table 37: MCLK Timing Parameter ............................................................................................................................. 97
NAU8812
emPowerAudio
™
Datasheet Revision 2.0 Page 12 of 109 January 2011
9. ABSOLUTE MAXIMUM RATINGS
CONDITION
MIN
MAX
Units
VDDB, VDDC, VDDA supply voltages
-0.3
+3.63
V
VDDSPK supply voltage (MOUT=0, SPKBST=0)
-0.3
+3.63
V
VDDSPK supply voltage (MOUTBST=1, SPKBST=1)
-0.3
+5.50
V
Core Digital Input Voltage range
VSSD – 0.3
VDDC + 0.30
V
Buffer Digital Input Voltage range
VSSD – 0.3
VDDB + 0.30
V
Analog Input Voltage range
VSSA – 0.3
VDDA + 0.30
V
Industrial operating temperature
-40
+85
0C
Storage temperature range
-65
+150
0C
CAUTION: Do not operate at or near the maximum ratings listed for extended period of time. Exposure to such
conditions may adversely influence product reliability and result in failures not covered by warranty. These devices
are sensitive to electrostatic discharge; follow proper IC Handling Procedures.
10. OPERATING CONDITIONS
Condition
Symbol
Min Value
Typical
Value
Max Value
Units
Analogue supplies range
VDDA
2.501
3.60
V
Digital supply range (Buffer)
VDDB
1.712
3.60
V
Digital supply range (Core)
VDDC
1.712
3.60
V
Speaker supply
VDDSPK
2.50
5.50
V
Ground
VSSD, VSSA,
VSSSPK
0
V
Note:
1. VDDA must be ≥ VDDC.
2. VDDB must be ≥ VDDC.
NAU8812
emPowerAudio
™
Datasheet Revision 2.0 Page 13 of 109 January 2011
11. ELECTRICAL CHARACTERISTICS
VDDC = 1.8V, VDDA = VDDB = SPKBST = 3.3V, TA = +25oC, 1kHz signal, fs = 48kHz, 24-bit audio data unless
otherwise stated.
PARAMETER
SYMBOL
TEST CONDITIONS
MIN
TYP
MAX
UNIT
Analogue to Digital Converter (ADC)
Full scale input signal 1
VINFS
PGABST = 0dB
PGAGAIN = 0dB
1.0
0
VRMS
dBV
Signal to Noise Ratio 2
SNR
Gain = 0dB, A-weighted
87
91
dB
Total Harmonic Distortion 3
THD
Input = -1dBFS, Gain = 0dB
-79
-65
dB
Digital to Analogue Converter (DAC) to MONO output (all data measured with 10kΩ / 50pF load)
Full Scale output signal 1
MOUTBST=0
1.0x
(VREF)
VRMS
MOUTBST=1
1.5 x
VREF
Signal to Noise Ratio 2
SNR
A-weighted (ADC/DAC oversampling rate
of 128)
90
93
dB
Total Harmonic Distortion 3
THD
RL = 10 kΩ; -1.0dBfs
-84
-70
dB
Auxiliary Analogue Input (AUX)
Full-scale Input Signal Level1
VINFS
Gain = 0dB
1
0
VRMS
dBV
Input Resistance
RAUX
AUXM=0
20
kΩ
Input Capacitance
CAUX
10
pF
Microphone Inputs (MICN & MICP) and MIC Input Programmable Gain Amplifier (PGA)
Full-scale Input Signal Level 1
VINFS
PGABST = 0dB
PGAGAIN = 0dB
1
0
VRMS
dBV
Programmable input PGA gain
-12
35.25
dB
Programmable Gain Step Size
Guaranteed monotonic
0.75
dB
Programmable Boost PGA gain
PGABST = 0
0
dB
PGABST = 1
20
Mute Attenuation
100
dB
PGA equivalent output noise
0 to 20kHz,
Gain set to 35.25dB
110
µV
Auxiliary Input resistance
RAUX
PGA Gain = 35.25dB
1.6
kΩ
PGA Gain = 0dB
47
kΩ
PGA Gain = -12dB
75
kΩ
Positive Microphone Input
resistance
RMIC+
PMICPGA = 1
94
kΩ
Input Capacitance
CMIC
10
pF
Speaker Output PGA
Programmable Gain
-57
6
dB
Programmable Gain Step Size
Guaranteed monotonic
1
dB
NAU8812
emPowerAudio
™
Datasheet Revision 2.0 Page 14 of 109 January 2011
VDDC = 1.8V, VDDA = VDDB = SPKBST = 3.3V, TA = +25oC, 1kHz signal, fs = 48kHz, 24-bit audio data unless
otherwise stated.
PARAMETER
SYMBOL
TEST CONDITIONS
MIN
TYP
MAX
UNIT
BTL Speaker Output (SPKOUT+, SPKOUT- with 8Ω bridge tied load)
Full scale output 7
SPKBST = 0
VDDSPK / 3.3
VRMS
SPKBST = 1
(VDDSPK / 3.3) * 1.5
Output Power
PO
Output power is very closely correlated with THD;
see below
Signal to Noise Ratio
SNR
VDDSPK = 3.3V
RL = 8Ω
90
dB
VDDSPK = 5V
RL = 8Ω
90
dB
Total Harmonic Distortion
THD
PO =180mW
RL = 8Ω
VDDSPK=3.3V
-63
dB
PO =400mW
-56
dB
PO =360mW
VDDSPK=5V
-60
dB
PO =800mW
-61
dB
PO =1W
-34
dB
Power Supply Rejection Ratio
(50Hz - 22kHz)
PSRR
VDDSPK = 3V, SPKBST = 0
50
dB
VDDSPK = 5V, SPKBST = 1
50
dB
Headphone’ output (SPKOUTP, SPKOUTN with resistive load to ground)
Full scale output 7
VREF
VRMS
Signal to Noise Ratio
SNR
A-weighted
90
dB
Total Harmonic Distortion
THD
Po = 20mW
RL=16Ω
VDDSPK=3.3V
-84
dB
Po = 20mW
RL=32Ω
-85
dB
Microphone Bias
Bias Voltage
VMICBIAS
(MICBIASV = 0)
0.9*
VDDA
V
(MICBIASV = 1)
0.65*
VDDA
V
Bias Current Source
IMICBIAS
3
mA
Output Noise Voltage
VN
MICBIASM = 0
(1kHz to 20kHz)
14
nV/√Hz
MICBIASM = 1
(1kHz to 20kHz)
4
nV/√Hz
Automatic Level Control (ALC)/Limiter – ADC only
Target Record Level
-28.5
-6
dB
Programmable Gain
-12
35.25
dB
Programmable Gain Step Size
Guaranteed Monotonic
0.75
dB
Gain Hold Time 4, 6
tHOLD
MCLK=12.288MHz
0 / 2.67 / …/ 43691
(time doubles with each
step)
ms
NAU8812
emPowerAudio
™
Datasheet Revision 2.0 Page 15 of 109 January 2011
VDDC = 1.8V, VDDA = VDDB = SPKBST = 3.3V, TA = +25oC, 1kHz signal, fs = 48kHz, 24-bit audio data unless
otherwise stated.
PARAMETER
SYMBOL
TEST CONDITIONS
MIN
TYP
MAX
UNIT
Automatic Level Control (ALC)/Limiter – ADC only
Gain Ramp-Up (Decay) Time 5, 6
tDCY
ALC Mode
ALCM=0
MCLK=12.288MHz
3.3 / 6.6 / 13.1 / … / 3360
(time doubles every step)
ms
Limiter Mode
ALCM=1
MCLK=12.288MHz
0.73 / 1.45 / 2.91 / … /
744 (time doubles every
step)
ms
Gain Ramp-Down (Attack) Time
5, 6
tATK
ALC Mode
ALCM=0
MCLK=12.288MHz
0.83 / 1.66 / 3.33 / … /
852 (time doubles every
step)
ms
Limiter Mode
ALCM=1
MCLK=12.288MHz
0.18 / 0.36 / 0.73 / … /
186 (time doubles every
step)
ms
Digital Input / Output
Input HIGH Level
VIH
0.7 ×
VDDC
V
Input LOW Level
VIL
0.3 ×
VDDC
V
Output HIGH Level
VOH
IOL = 1mA
0.9 ×
VDDC
V
Output LOW Level
VOL
IOH = -1mA
3.25
0.1 x
VDDC
V
Notes
1. Full Scale is relative to VDDA (FS = VDDA/3.3.). Input level to AUX is limited to a maximum of -3dB so that
THD+N performance will not be reduced.
2. Signal-to-noise ratio (dB) - SNR is a measure of the difference in level between the full-scale output and the
output with no signal applied. (No Auto-zero or Automute function is employed in achieving these results).
3. THD+N (dB) - THD+N are a ratio, of the rms values, of (Noise + Distortion)/Signal.
4. Hold Time is the length of time between a signal detected being too quiet and beginning to ramp up the gain. It
does not apply to ramping down the gain when the signal is too loud, which happens without a delay.
5. Ramp-up and Ramp-Down times are defined as the time it takes to change the PGA gain by 6dB of its gain
range.
6. All hold, ramp-up and ramp-down times scale proportionally with MCLK
7. The maximum output voltage can be limited by the speaker power supply. If MOUTBST or SPKBST is, set then
VDDSPK should be 1.5xVDDA to prevent clipping taking place in the output stage (when PGA gains are set to 0dB).
NAU8812
emPowerAudio
™
Datasheet Revision 2.0 Page 16 of 109 January 2011
12. FUNCTIONAL DESCRIPTION
The NAU8812 is a MONO Audio CODEC with very robust ADC and DAC. The device provides one single ended
auxiliary input (AUX pin) and one differential microphone input (MIC- & MIC+ pins). The auxiliary input (AUX) can be
configured to sum multiple signals into a single input. It has three different amplification paths with a total gain of up
to +55.25dB. The differential input also has amplification paths similar to auxiliary input.
The device also has an internal configurable biasing circuit for biasing the microphone, which in turn reduces external
components. The PGA output has programmable ADC gain. An advanced Sigma Delta DAC is used along with
digital decimation and interpolation filters to give high quality audio at sample rates from 8 kHz to 48 kHz. The Digital
Filter blocks include ADC high pass filters, and Notch filter. The device has two output mixers, one for MONO output
and the other for the speaker output. It also has one input mixer.
The NAU8812 has two different types of serial control interface 2-Wire and SPI for device control. 2-Wire and SPI
are hardware selectable through MODE pin on the device. The device also supports I2S, PCM time slotting, Left
Justified and Right Justified for audio interface.
The device can operate as a master or slave device. It can operate with sample rates ranging from 8 kHz to 48 kHz,
depending on the values of MCLK and its prescaler. The NAU8812 includes a PLL block, where it takes the external
clock (MCLK pin) to generate other clocks for the audio data transfer such as Bit clock (BCLK), Frame sync (FS), and
I2S clocks. The PLL can also configure a separate programmable clock for the use in the system through CSb/GPIO
pin. The power control registers help save power by controlling the major individual functional blocks of the NAU8812.
12.1. INPUT PATH
The NAU8812 has two different types of microphone inputs single ended and differential. Figure 3 shows the
different paths that the input signals can take.
All inputs are maintained at a DC bias at approximately half of the VDDA supply voltage. Connections to these inputs
should be AC-coupled by means of DC blocking capacitors suitable for the device application.
12.1.1. The Single Ended Auxiliary Input (AUX)
The single ended auxiliary input (AUX) has three different paths to MONO output (MOUT).
Directly connected to the MONO Mixer or Speaker Mixer to MOUT or SPKOUT+ and SPKOUT- respectively
Connect through the PGA Boost Mixer which has a range of -12dB to +6dB
Connect through both the input PGA Gain (range of -12dB to +35.25 dB) and PGA Boost Mixer (range of 0db or
+20dB)
NAU8812
emPowerAudio
™
Datasheet Revision 2.0 Page 17 of 109 January 2011
The last two paths above go through the ADC filters where the ALC loop controls the amplitude of the input signal.
The device also has an internal configurable biasing circuit for biasing the microphone, reducing external
components.
An internal inverting operational amplifier circuit allows the auxiliary input pin to connect multiple signals for mixing.
This can be achieved by setting AUXM[3] address (0x2C) to LOW. The combination of the 20k ohm resistors can
vary due to process variation in the gain stage. The block can also be configured to be used as a buffer by setting
AUXM[3] address (0x2C) to HIGH. The internal inverting circuit block can be enable/disable by setting AUXEN[6]
address (0x01).
Figure 4: Auxiliary Input Circuit Block Diagram with AUXM[3] = 0
Figure 5: Auxiliary Input Circuit Block Diagram with AUXM[3] = 1
AUX
Pin
20k20k
VREF
AUXM[3]
(0x2C)
Output to
PGA Gain
MONO Mixer
Speaker Mixer
R
AUXEN[6]
(0x01)
AUXM[3]
(0x2C)
AUX
Pin
20k20k
VREF
AUXM[3]
(0x2C)
Output to
PGA Gain
MONO Mixer
Speaker Mixer
R
R
R
AUXEN[6]
(0x01)
AUXM[3]
(0x2C)
NAU8812
emPowerAudio
™
Datasheet Revision 2.0 Page 18 of 109 January 2011
12.1.2. The differential microphone input (MIC- & MIC+ pins)
The NAU8812 features a low-noise, high common mode rejection ratio (CMRR), differential microphone inputs (MIC-
& MIC+ pins) which are connected to a PGA Gain stage. The differential input structure is essential in noisy digital
systems where amplification of low-amplitude analog signals is necessary such as notebooks and PDAs. When
properly employed, the differential input architecture offers an improved power-supply rejection ratio (PSRR) and
higher ground noise immunity.
Figure 6: Input PGA Circuit Block Diagram
Bit(s)
Addr
Parameter
Programmable Range
PMICPGA[0]
0x2C
Positive Microphone to PGA
0 = Input PGA Positive terminal to VREF
1 = Input PGA Positive terminal to MICP
NMICPGA[1]
0x2C
Negative Microphone to PGA
0 = MICN not connected to input PGA
1 = MICN to input PGA Negative terminal.
Table 2: Register associated with Input PGA Contro
R
PGAGAIN[5:0]
(0x2D)
MIC+
MIC-
VREF
From AUX
stage
PGAGAIN[5:0]
(0x2D)
-12 dB to +35.25 dB
To PGA
Boost
NMICPGA[1]
(0x2C)
AUXPGA[2]
(0x2C)
PMICPGA[0]
(0x2C)
NMICPGA[1]
(0x2C)
AUXPGA[2]
(0x2C)
R
R
R
R
PGAGAIN[5:0]
(0x2D)
NAU8812
emPowerAudio
™
Datasheet Revision 2.0 Page 19 of 109 January 2011
12.1.2.1. Positive Microphone Input (MIC+)
The positive microphone input (MIC+) can be used as part of the differential input. It connects to the positive terminal
of the PGA gain amplifier by setting PMICPGA[0] address (0x2C) to HIGH or can be connected to VREF by setting
PMICPGA[0] address (0x2C) to LOW.
When the associated control bit is set logic = 1, the MIC+ pin is connected to a resistor of approximately 1kΩ which is
tied to VREF. The purpose of the tie to VREF is to reduce any pop or click sound by keeping the DC level of the
MIC+ pin close to VREF at all times.
Note: In single ended applications where the MIC+ input is used without using MIC-, the PGA gain values will be
valid only if the MIC- pin is terminated to a low impedance signal point. This termination should normally be an AC
coupled path to signal ground. This input impedance is constant regardless of the gain value. The following table
gives the nominal input impedance for this input. Impedance for specific gain values not listed in this table can be
estimated through interpolation between listed values.
MIC+ to non-inverting PGA input
Nominal Input Impedance
MIC- to inverting PGA input
Nominal Input Impedance
Gain (dB)
Impedance (kΩ)
Gain (dB)
Impedance (kΩ)
-12
94
-12
75
-9
94
-9
69
-6
94
-6
63
-3
94
-3
55
0
94
0
47
3
94
3
39
6
94
6
31
9
94
9
25
12
94
12
19
18
94
18
11
30
94
30
2.9
35.25
94
35.25
1.6
Table 3: Microphone Non-Inverting
Input Impedances
Table 4: Microphone Inverting Input
Impedances
12.1.2.2. Negative Microphone Input (MIC-)
The negative microphone input (MIC-) has two distinctive configuration; differential input or single ended input. This
input connects to the negative terminal of the PGA gain amplifier by setting NMICPGA[1] address (0x2C) to HIGH.
When the MIC- is used as a single ended input, MIC+ should be conned to VREF by setting PMICPGA[0] address
(0x2C) bit to LOW. The AUX input signal can also be mixed with the MIC- input signal by setting AUXPGA[2]
address (0x2C) to HIGH.
NAU8812
emPowerAudio
™
Datasheet Revision 2.0 Page 20 of 109 January 2011
When the associated control bit is set logic = 1, the MIC- pin is connected to a resistor of approximately 30kΩ which
is tied to VREF. The purpose of the tie to VREF is to reduce any pop or click sound by keeping the DC level of the
MIC- pin close to VREF at all times. It is important for a system designer to know that the MIC-input impedance
varies as a function of the selected PGA gain. This is normal and expected for a difference amplifier type topology.
The above table gives the nominal resistive impedance values for this input over the possible gain range. Impedance
for specific gain values not listed in this table can be estimated through interpolation between listed values.
12.1.2.3. PGA Gain Control
The PGA amplification is common to all three input pins MIC-, MIC+, AUX, and enabled by PGAEN[2] address
(0x02). It has a range of -12dB to +35.25dB in 0.75dB steps, controlled by PGAGAIN[5:0] address (0x2D). Input
PGA gain will not be used when ALC is enabled using ALCEN[8] address (0x20).
Addr
Bit 8
Bit 7
Bit 6
Bit5
Bit 4
Bit 3
Bit 2
Bit 1
Bit 0
Default
0x2D
0
PGAZC
PGAMT
PGAGAIN[5:0]
0x010
0x20
ALCEN
0
0
ALCMXGAIN[2:0]
ALCMNGAIN[2:0]
0x038
Table 5: Registers associated with ALC and Input PGA Gain Control
12.1.3. PGA Boost Stage
The boost stage has three inputs connected to the PGA Boost Mixer. All three inputs can be individually connected
or disconnected from the PGA Boost Mixer. The boost stage can be enabled by setting BSTEN[4] address (0x02) to
HIGH. The following figure shows the PGA Boost stage.
Figure 7: Boost Stage Block Diagram
AUXBSTGAIN[2:0]
(0x2F)
PMICBSTGAIN[6:4]
(0x2F)
PGAMT[6]
(0x2D)
PGABST[8]
(0x2F)
Output from
AUX stage
Output from
PGA Gain
MIC+
Pin
To ADC
NAU8812
emPowerAudio
™
Datasheet Revision 2.0 Page 21 of 109 January 2011
The signal from AUX stage can be amplified at the PGA Boost stage before connecting to the Boost Mixer by setting
a binary value from “001” - “111” to AUXBSTGAIN[2:0] address (0x2F). The path is disconnected by setting “000” to
the AUXBSTGAIN bits.
Signal from PGA stage to the PGA Boost Mixer is disconnected or muted by setting PGAMT[6] address (0x2D) to
HIGH. In this path the PGA boost can be a fixed value of +20dB or 0dB, controlled by the PGABST[8] address
(0x2F) bit.
The signal from MIC+ pin to the PGA Boost Mixer is disconnected by setting „000‟ binary value to PMICBSTGAIN[6:4]
address (0x2F) and any other combination connects the path.
Bit(s)
Addr
Parameter
Programmable Range
BSTEN[4]
0x02
Enable PGA Boost Block
0 = Boost stage OFF
1 = Boost stage ON
PGAMT[6]
0x2D
Mute control for input PGA
0=Input PGA not muted
1=Input PGA muted
AUXBSTGAIN[2:0]
0x2F
Boost AUX signal
Range: -12dB to +6dB @ 3dB increment
PMICBSTGAIN[6:4]
0x2F
Boost MIC+ signal
Range: -12dB to +6dB @ 3dB increment
PGABST[8]
0x2F
Boost PGA stage
0 = PGA output has +0dB
1 = PGA output has +20dB
Table 6: Registers associated with PGA Boost Stage Control
NAU8812
emPowerAudio
™
Datasheet Revision 2.0 Page 22 of 109 January 2011
12.2. MICROPHONE BIASING
Figure 8: Microphone Bias Schematic
The MICBIAS pin is a low-noise microphone bias source for an external microphone, which can provide a maximum
of 3mA of bias current. This DC bias voltage is suitable for powering either traditional ECM (electret) type
microphones, or for MEMS types microphones with an independent power supply pin. Seven different bias voltages
are available for optimum system performance, depending on the specific application. The microphone bias pin
normally requires an external filtering capacitor as shown on the schematic in the Application section.
The output bias can be enabled by setting MICBIASEN[4] address (0x01) to HIGH. It has various voltage values
selected by a combination of bits MICBIASM[4] address (0x3A) and MICBIASV[8:7] address (0x2C).
The low-noise feature results in greatly reduced noise in the external MICBIAS voltage by placing a resistor of
approximately 200-ohms in series with the output pin. This creates a low pass filter in conjunction with the external
microphone-bias filter capacitor, but without any additional external components.
Bit(s)
Addr
Parameter
Programmable Range
MICBIASEN[4]
0x01
Microphone bias enable
0 = Disable
1 = Enable
MICBIASM[4]
(0x3A)
Microphone bias mode selection
MICBIASV[8:7]
(0x2C)
Microphone bias voltage selection
0 = Disable
1 = Enable
Table 7: Register associated with Microphone Bias
Below are the unloaded values when MICBIASM[4] is set to 1 and 0. When loaded, the series resistor will cause the
voltage to drop, depending on the load current.
R
VREF
R
MICBIAS
MICBIASM[0]
(0x28)
MICBIASV[1:0]
(0x2C)
NAU8812
emPowerAudio
™
Datasheet Revision 2.0 Page 23 of 109 January 2011
Microphone Bias Voltage Control
MICBIASV[8:7]
MICBIASM[4] = 0
MICBIASM[4]= 1
0
0
0.9* VDDA
0.85* VDDA
0
1
0.65* VDDA
0.60* VDDA
1
0
0.75* VDDA
0.70* VDDA
1
1
0.50* VDDA
0.50* VDDA
Table 8: Microphone Bias Voltage Control
NAU8812
emPowerAudio
™
Datasheet Revision 2.0 Page 24 of 109 January 2011
12.3. ADC DIGITAL FILTER BLOCK
Figure 9: ADC Digital Filter Path Block Diagram
The ADC digital filter block performs a 24-bit signal processing. The block consists of an oversampled analog sigma-
delta modulator, digital decimator, digital filter, high pass filter, and a notch filter. The oversampled analog sigma-
delta modulator provides a bit stream to the decimation stages and filter. The ADC coding scheme is in twos-
complement format and the full-scale input level is proportional to VDDA. With a 3.3V supply voltage, the full-scale
level is 1.0VRMS and any voltage greater than full scale may overload the ADC and cause distortion. The ADC is
enabled by setting ADCEN[0] address (0x02) bit. Polarity and oversampling rate of the ADC output signal can be
changed by ADCPL[0] address (0x0E) and ADCOS[3] address (0x0E) respectively.
Bit(s)
Addr
Parameter
Programmable Range
ADCPL[0]
0x0E
ADC Polarity
0 = Normal
1 = Inverted
ADCOS[3]
0x0E
ADC Over Sample
Rate
0=64x (Lowest power)
1=128x (best SNR at typical condition)
HPFEN[8]
0x0E
High Pass Filter
Enable
0 = Disable
1 = Enable
HPFAM[7]
0x0E
Audio or Application Mode
0 = Audio (1st order, fc ~ 3.7 kHz)
1 = Application (2nd order, fc =HPF)
HPF[6:4]
0x0E
High Pass Filter frequencies
82 Hz to 612 Hz dependant on the sample rate
ADCEN[0]
0x02
Enable ADC
0 = Disable
1 = Enable
SMPLR[3:1]
0x07
Sample rate
8k Hz to 48 kHz
Table 9: Register associated with ADC
ADC Digital Filters
ADC Digital
Decimator /
Digital
Filter Gain High
Pass
Filter
Notch
Filter
Digital
Audio
Interface
NAU8812
emPowerAudio
™
Datasheet Revision 2.0 Page 25 of 109 January 2011
12.3.1. Programmable High Pass Filter (HPF)
The high pass filter (HPF) has two different modes that it can operate in either Audio or Application mode HPFAM[7]
address (0x0E). In Audio Mode (HPFAM=0) the filter is first order, with a cut-off frequency of 3.7kHz. In Application
mode (HPFAM=1) the filter is second order, with a cut-off frequency selectable via the HPF[2:0] register bits. Cut-off
frequency of the HPF depends on sample frequency selected by SMPLR[3:1] address (0x07). The HPF is enabled
by setting HPFEN[8] address (0x0E) to HIGH. Table below shows the cut-off frequencies with different sampling
rate.
HPF[2:0]
fs (kHz)
SMPLR=101/100
SMPLR=011/010
SMPLR=001/000
8
11.025
12
16
22.05
24
32
44.1
48
000
82
113
122
82
113
122
82
113
122
001
102
141
153
102
141
153
102
141
153
010
131
180
156
131
180
156
131
180
156
011
163
225
245
163
225
245
163
225
245
100
204
281
306
204
281
306
204
281
306
101
261
360
392
261
360
392
261
360
392
110
327
450
490
327
450
490
327
450
490
111
408
563
612
408
563
612
408
563
612
Table 10: High Pass Filter Cut-off Frequencies (HPFAM=1)
12.3.2. Programmable Notch Filter (NF)
The NAU8812 has a programmable notch filter where it passes all frequencies except those in a stop band centered
on a given center frequency. The filter gives lower distortion and flattens response. The notch filter is enabled by
setting NFCEN[7] address (0x1B) to HIGH. The variable center frequency is programmed by setting two‟s
complement values to NFCA0[6:0] address (0x1C), NFCA0[13:7] address (0x1B) and NFCA1[6:0] address (0x1E),
NFCA1[13:7] address (0x1D) registers. The coefficients are updated in the circuit when the NFCU[8] bit is set HIGH
in a write to any of the registers NF1-NF4 address (0x1B, 0x1C, 0x1D, 0x1E).
Addr
Bit 8
Bit 7
Bit 6
Bit5
Bit 4
Bit 3
Bit 2
Bit 1
Bit 0
Default
0x1B
NFCU
NFCEN
NFCA0[13:7]
0x000
0x1C
NFCU
0
NFCA0[6:0]
0x000
0x1D
NFCU
0
NFCA1[13:7]
0x000
0x1E
NFCU
0
NFCA1[6:0]
0x000
Table 11: Registers associated with Notch Filter Function
NAU8812
emPowerAudio
™
Datasheet Revision 2.0 Page 26 of 109 January 2011
A0
A1
Notation
Register Value (DEC)
Coefficient
s
b
s
b
f
f
f
f
2
2
1
2
2
1
tan
tan
s
c
f
f
xA
2
10cos
fc = center frequency (Hz)
fb = -3dB bandwidth (Hz)
fs = sample frequency
(Hz)
NFCA0 = -A0 x 213
NFCA1 = -A1 x 212
(then convert to 2‟s
complement)
Table 12: Equations to Calculate Notch Filter Coefficients
12.3.3. Digital ADC Gain Control
The digital ADC can be muted by setting “0000 0000” to ADCGAIN[7:0] address (0x0F). Any other combination
digitally attenuates the ADC output signal in the range -127dB to 0dB in 0.5dB increments].
Addr
Name
Bit 8
Bit 7
Bit 6
Bit5
Bit 4
Bit 3
Bit 2
Bit 1
Bit 0
Default
0x0F
ADCG
0
ADCGAIN
0x0FF
Table 13: Register associated with ADC Gain
12.4. PROGRAMMABLE GAIN AMPLIFIER (PGA)
NAU8812 has a programmable gain amplifier (PGA) which controls the gain such that the signal level of the PGA
remains substantially constant as the input signal level varies within a specified dynamic range. The PGA has two
functions
Automatic level control (ALC) or
Input peak limiter
The Automatic Level Control (ALC) seeks to control the PGA gain in response to the amplitude of the input signal
such that the PGA output maintains a constant envelope. A digital peak detector monitors the input signal amplitude
and compares it to a register defined threshold level ALCSL[3:0] address (0x21). Note: When the ALC automatic
level control is enabled, the function of the ALC is to automatically adjust PGAGAIN[5:0] address (0x2D) volume
setting.
12.4.1. Automatic level control (ALC)
The ALC seeks to control the PGA gain such that the PGA output maintains a constant envelope. This helps to
prevent clipping at the input of the sigma delta ADC while maximizing the full dynamic range of the ADC. The ALC
monitors the output of the ADC, measured after the digital decimator has converted it to 1.23 fixed-point formats. The
ADC output is fed into a peak detector, which updates the measured peak value whenever the absolute value of the
input signal is higher than the current measured peak. The measured peak gradually decays to zero unless a new
peak is detected, allowing for an accurate measurement of the signal envelope. Based on a comparison between the
measured peak value and the target value, the ALC block adjusts the gain control, which is fed back to the PGA.
NAU8812
emPowerAudio
™
Datasheet Revision 2.0 Page 27 of 109 January 2011
Figure 10: ALC Block Diagram
The ALC is enabled by setting ALCEN[8] address (0x20) bit to HIGH. The ALC has two functional modes, which is
set by ALCM[8] address (0x22).
Normal mode (ALCM = LOW)
Peak Limiter mode (ALCM = HIGH)
When the ALC is disabled, the input PGA remains at the last controlled value of the ALC. An input gain update must
be made by writing to the PGAGAIN[5:0] address (0x2D). A digital peak detector monitors the input signal amplitude
and compares it to a register defined threshold level ALCSL[3:0] address (0x21).
Figure 11: ALC Response Graph
The registers listed in the following section allow configuration of ALC operation with respect to:
ALC target level
Gain increment and decrement rates
Minimum and maximum PGA gain values for ALC operating range
Hold time before gain increments in response to input signal
ALC operation range
Target ALCSL -6dB Gain (Attenuation) Clipped
at ALCMNGAIN -12dB
Output Level
-39dB
-39dB -6dB +6dB
-12 dB
0 dB
+33 dB
Input Level
Input < noise
gate threshold
ALCNEN = 1
ALCNTH = -39dB
MIC Boost Gain = 0dB
ALCSL = -6dB
ALCMNGAIN = -12dB
ALCMXGAIN = +35.25dB
PGA Gain
PGA ADC Sinc
Filter Digital
Decimator
ALC
Rate Convert/ Decimator
Input
Pin Digital
Filter
NAU8812
emPowerAudio
™
Datasheet Revision 2.0 Page 28 of 109 January 2011
Inhibition of gain increment during noise inputs
Limiter mode operation
Bit(s)
Addr
Parameter
Programmable Range
ALCMNGAIN[2:0]
0x20
Minimum Gain of PGA
Range: -12dB to +30dB @ 6dB increment
ALCMXGAIN[2:0]
Maximum Gain of PGA
Range: -6.75dB to +35.25dB @ 6dB increment
ALCEN[8]
Enable ALC function
0 = Disable
1 = Enable
ALCSL[3:0]
0x21
ALC Target
Range: -28.5dB to -6dB @ 1.5dB increment
ALCHT[3:0]
ALC Hold Time
Range: 0ms to 1s, time doubles with every step)
ALCZC[8]
ALC Zero Crossing
0 = Disable
1 = Enable
ALCATK[3:0]
0x22
ALC Attack time
ALCM=0 - Range: 125us to 128ms
ALCM=1 - Range: 31us to 32ms (time doubles with
every step)
ALCDCY[3:0]
ALC Decay time
ALCM=0 - Range: 500us to 512ms
ALCM=1 - Range: 125us to 128ms
(Both ALC time doubles with every step)
ALCM[8]
ALC Select
0 = ALC mode
1 = Limiter mode
Table 14: Registers associated with ALC Control
The operating range of the ALC is set by ALCMXGAIN[5:3] address (0x20) and ALCMNGAIN[2:0] address (0x20) bits
such that the PGA gain generated by the ALC is between the programmed minimum and maximum levels. When the
ALC is enabled, the PGA gain is disabled.
In Normal mode, the ALCMXGAIN bits set the maximum level for the PGA in the ALC mode but in the Limiter mode
ALCMXGAIN has no effect because the maximum level is set by the initial PGA gain setting upon enabling of the
ALC.
ALCMAXGAIN
Maximum Gain (dB)
ALCMINGAIN
Minimum Gain (dB)
111
35.25
000
-12
110
29.25
001
-6
ALC Max Gain Range 35.25dB to -6dB @
6dB increments
ALC Min Gain Range -12dB to 30dB @
6dB increments
001
-0.75
110
24
000
-6.75
111
30
Table 15: ALC Maximum and Minimum Gain Values
NAU8812
emPowerAudio
™
Datasheet Revision 2.0 Page 29 of 109 January 2011
12.4.1.1. Normal Mode
Normal mode is selected when ALCM[8] address (0x22) is set LOW and the ALC is enabled by setting ALCEN[8]
address (0x20) HIGH. This block adjusts the PGA gain setting up and down in response to the input level. A peak
detector circuit measures the envelope of the input signal and compares it to the target level set by ALCSL[3:0]
address (0x21). The ALC increases the gain when the measured envelope is greater than the target and decreases
the gain when the measured envelope is less than - 1.5dB. The following waveform illustrates the behavior of the
ALC.
Figure 12: ALC Normal Mode Operation
12.4.1.2. ALC Hold Time (Normal mode Only)
The hold parameter ALCHT[3:0] configures the time between detection of the input signal envelope being outside of
the target range and the actual gain increase.
Input signals with different characteristics (e.g., voice vs. music) may require different settings for this parameter for
optimal performance. Increasing the ALC hold time prevents the ALC from reacting too quickly to brief periods of
silence such as those that may appear in music recordings; having a shorter hold time, on the other hand, may be
useful in voice applications where a faster reaction time helps to adjust the volume setting for speakers with different
volumes. The waveform below shows the operation of the ALCHT parameter.
PGA Input
PGA Output
PGA Gain
NAU8812
emPowerAudio
™
Datasheet Revision 2.0 Page 30 of 109 January 2011
Figure 13: ALC Hold Time
12.4.2. Peak Limiter Mode
Peak Limiter mode is selected when ALCM[8] address (0x22) is set to HIGH and the ALC is enabled by setting
ALCEN[8] address (0x20). In limiter mode, the PGA gain is constrained to be less than or equal to the gain setting at
the time the limiter mode is enabled. In addition, attack and decay times are faster in limiter mode than in normal
mode as indicated by the different lookup tables for these parameters for limiter mode. The following waveform
illustrates the behavior of the ALC in Limiter mode in response to changes in various ALC parameters.
Figure 14: ALC Limiter Mode Operations
When the input signal exceeds 87.5% of full scale, the ALC block ramps down the PGA gain at the maximum attack
rate (ALCATK=0000) regardless of the mode and attack rate settings until the ADC output level has been reduced
below the threshold. This limits ADC clipping if there is a sudden increase in the input signal level.
Limiter
Enabled
PGA Gain
PGA Input
PGA
Output
Hold Delay
Change
PGA Gain
PGA Input
PGA Output
NAU8812
emPowerAudio
™
Datasheet Revision 2.0 Page 31 of 109 January 2011
12.4.3. Attack Time
When the absolute value of the ADC output exceeds the level set by the ALC threshold, ALCSL[3:0] address (0x21),
attack mode is initiated at a rate controlled by the attack rate register ALCATK[3:0] address (0x22). The peak
detector in the ALC block loads the ADC output value when the absolute value of the ADC output exceeds the current
measured peak; otherwise, the peak decays towards zero, until a new peak has been identified. This sequence is
continuously running. If the peak is ever below the target threshold, then there is no gain decrease at the next attack
timer time; if it is ever above the target-1.5dB, then there is no gain increase at the next decay timer time.
12.4.4. Decay Times
The decay time ALCDCY[6:4] address (0x22) is the time constant used when the gain is increasing. In limiter mode,
the time constants are faster than in ALC mode.
12.4.5. Noise gate (normal mode only)
A noise gate is used when there is no input signal or the noise level is below the noise gate threshold. The noise
gate is enabled by setting ALCNEN[3] address (0x23) to HIGH. It does not remove noise from the signal. The noise
gate threshold ALCNTH[2:0] address (0x23) is set to a desired level so when there is no signal or a very quiet signal
(pause), which is composed mostly of noise, the ALC holds the gain constant instead of amplifying the signal towards
the target threshold. The noise gate only operates in conjunction with the ALC and ONLY in Normal mode. The
noise gate flag is asserted when
(Signal at ADC – PGA gain – MIC Boost gain) < ALCNTH (ALC Noise Gate Threshold) (dB)
Levels at the extremes of the range may cause inappropriate operation, so care should be taken when setting up the
function.
Figure 15: ALC Operation with Noise Gate disabled
PGA Input
PGA Output
PGA Gain
NAU8812
emPowerAudio
™
Datasheet Revision 2.0 Page 32 of 109 January 2011
Figure 16: ALC Operation with Noise Gate Enabled
12.4.6. Zero Crossing
The PGA gain comes from either the ALC block when it is enabled or from the PGA gain register setting when the
ALC is disabled. Zero crossing detection may be enabled to cause PGA gain changes to occur only at an input zero
crossing. Enabling zero crossing detection limits clicks and pops that may occur if the gain changes while the input
signal has a high volume.
There are two zero crossing detection enables:
Register ALCZC[8] address (0x21) – is only relevant when the ALC is enabled.
Register PGAZC[7] address (0x2D) – is only relevant when the ALC is disabled.
If the zero crossing function is enabled (using either register) and SCLKEN[0] address (0x07) is asserted, the zero
cross timeout function may take effect. If the zero crossing flag does not change polarity within 0.25 seconds of a
PGA gain update (either via ALC update or PGA gain register update), then the gain will update. This backup system
prevents the gain from locking up if the input signal has a small swing and a DC offset that prevents the zero crossing
flag from toggling.
PGA Input
PGA Output
PGA Gain
Noise Gate Threshold
NAU8812
emPowerAudio
™
Datasheet Revision 2.0 Page 33 of 109 January 2011
12.5. DAC DIGITAL FILTER BLOCK
Figure 17: DAC Digital Filter Path
The DAC digital block uses 24-bit signal processing to generate analog audio with a 16-bit digital sample stream
input. This block consists of a sigma-delta modulator, high pass filter, digital gain/filters, de-emphasis, and analog
mixers. The DAC coding scheme is in twos complement format and the full-scale output level is proportional to
VDDA. With a 3.3V supply voltage, the full-scale output level is 1.0VRMS. The DAC is enabled by setting DACEN[0]
address (0x03) bit HIGH.
Bit(s)
Addr
Parameter
Programmable Range
DACEN[0]
0x03
DAC enable
0 = Disable
1 = Enable
ADDAP[0]
0x05
Pass-through of ADC output data
into DAC input
0 = Disable
1 = Enable
DACPL[0]
0x0A
DAC Polarity
0 = No Inversion
1 = DAC Output Inverted
AUTOMT[2]
Auto Mute
0 = Disable
1 = Enable
DEEMP[5:4]
Sample Rate
32 kHz, 44.1 kHz, and 48 kHz
DACMT[6]
Soft Mute
0 = Disable
1 = Enable
DACGAIN[7:0]
0x0B
DAC Volume Control
Range: -127dB to 0dB @ 0.5dB
increment, 00 hex is Muted
DACLIMATK[3:0]
0x18
DAC Limiter Attack
Range: 68us to 139ms
DACLIMDCY[7:4]
DAC Limiter Decay
Range: 544us to 1.1s
DACLIMEN[8]
DAC Limiter Enable
0 = Disable
1 = Enable
DACLIMBST[3:0]
0x19
DAC Limiter Volume Boost
Range: 0dB to +12dB @ 1dB increment
DACLIMTHL[6:4]
DAC Limiter Threshold
Range: -6dB to -1bB @ 1dB increment
Table 16: Registers associated with DAC Gain Control
Digital
Gain
Digital
Peak
Limiter
Digital
Filters Interpo-
lation
Sigma
Delta
Modulator
DAC Digital Filters
Digital
Audio
Interface DAC
NAU8812
emPowerAudio
™
Datasheet Revision 2.0 Page 34 of 109 January 2011
12.5.1. DAC Soft Mute
The NAU8812 also has a Soft Mute function, which gradually attenuates the volume of the digital signal to zero.
When removed, the gain will ramp back up to the digital gain setting. This function is disabled by default. This
feature provides a tool that is useful for using the DACs without introducing pop and click sounds. To play back an
audio signal, it must first be disabled by setting the DACMT[6] address (0x0A) bit to LOW.
12.5.2. DAC Auto Mute
The output of the DAC can be muted by the analog auto mute function. The auto mute function is enabled by setting
AUTOMT[2] address (0x0A) to HIGH and applied to the DAC output when it sees 1024 consecutive zeros at its input.
If at any time there is a non-zero sample value, the DAC will be un-muted, and the 1024 count will be reinitialized to
zero.
12.5.3. DAC Sampling / Oversampling rate, Polarity, DAC Volume control and Digital Pass-through
The sampling rate of the DAC is determined entirely by the frequency of its input clock and the oversampling rate
setting. The oversampling rate of the DAC can be changed to 64x or 128x. In the 128x oversampling mode it gives
an improved audio performance at slightly higher power consumption. Because the additional supply current is only
1mA, in most applications the 128x oversampling is preferred for maximum audio performance.
The polarity of the DAC output signal can be changed as a feature sometimes useful in management of the audio
phase. This feature can help minimize any audio processing that may be otherwise required as the data are passed
to other stages in the system.
The effective output audio volume of the DAC can be changed using the digital volume control feature. This
processes the output of the DAC to scale the output by the amount indicated in the volume register setting. Included
is a “digital mute” value which will completely mute the signal output of the DAC. The digital volume setting can
range from 0dB through -127dB in 0.5dB steps.
Digital audio pass-through allows the output of the ADC to be directly sent to the DAC as the input signal to the DAC
for DAC output. In this mode of operation, the external digital audio signal for the DAC will be ignored. The pass-
through function is useful for many test and application purposes, and the DAC output may be utilized in any way that
is normally supported for the DAC analog output signals.
12.5.4. Hi-Fi DAC De-Emphasis and Gain Control
The NAU8812 has Hi-Fi DAC gain control for signal conditioning. The level of attenuation for an eight-bit code X is
given by: 0.5 × (X-255) dB for 1 ≤ X ≤ 255; MUTE for X = 0
It includes on-chip digital de-emphasis and is available for sample rates of 32 kHz, 44.1 kHz, and 48 kHz. The digital
de-emphasis can be enabled by setting DEEMP[5:4] address (0x0A) bits depending on the input sample rate. The
NAU8812
emPowerAudio
™
Datasheet Revision 2.0 Page 35 of 109 January 2011
de-emphasis feature is included to accommodate audio recordings that utilize 50/15 s pre-emphasis equalization as
a means of noise reduction. The DAC output can be inverted (phase inversion) by setting DACPL[1:0] address
(0x0A) to HIGH, non-inverted output is set by default.
12.5.5. Digital DAC Output Peak Limiter
Output Peak-Limiters reduce the dynamic range by ensuring the signal will not exceed a certain threshold, while
maximizing the RMS of the resulted audio signal, and minimizing audible distortions. NAU8812 has a digital output
limiter function. In the figure below, the upper graph shows the envelope of the input/output signals and the lower
graph shows the gain characteristic. The limiter has a programmable threshold, DACLIMTHL[6:4] address (0x19),
which ranges from -1dB to -6dB in 1dB increments. The digital peak limiter seeks to keep the envelope of the output
signal within the target threshold +/- 0.5dB. The attack and decay rates programmed in registers DACLIMATK[3:0]
address (0x18) and DACLIMDCY[7:4] address (0x18) specify how fast the digital peak limiter decrease and increase
the gain, respectively, in response to the envelope of the output signal falling outside of this range. In normal
operation LIMBST=000 signals below this threshold are unaffected by the limiter.
Figure 18: DAC Digital Limiter Control
12.5.6. Volume Boost
The limiter has programmable upper gain, which boosts signals below the threshold to compress the dynamic range
of the signal and increase its perceived loudness. This operates as an ALC function with limited boost capability.
The volume boost is from 0dB to +12dB in 1dB steps, controlled by the DACLIMBST[3:0] register bits. The output
limiter volume boost can also be used as a stand-alone digital gain boost when the limiter is disabled.
DAC Input
Data
DAC Output
Signal
Digital Gain 0dB
-1dB
-0.5dB
Threshold
-1dB
NAU8812
emPowerAudio
™
Datasheet Revision 2.0 Page 36 of 109 January 2011
12.6. ANALOG OUTPUTS
The NAU8812 features two different types of outputs, a single-ended MONO output (MOUT) and a differential
speaker outputs (SPKOUT+ and SPKOUT-). The speaker amplifiers designed to drive a load differentially; a
configuration referred to as Bridge-Tied Load (BTL).
Figure 19: Speaker and MONO Analogue Outputs
12.6.1. Speaker Mixer Outputs
The speaker amplifiers are designed to drive a load differentially; a configuration referred to as Bridge-Tied Load
(BTL). The differential speaker outputs can drive a single 8Ω speaker or two headphone loads of 16Ω or 32Ω or a
line output. Driving the load differentially doubles the output voltage. The output of the speaker can be manipulated
by changing attenuation and the volume (loudness of the output signal).
The output stage is powered by the speaker supply, VDDSPK, which are capable of driving up to 1.5VRMS signals
(equivalent to 3VRMS into a BTL speaker). The speaker outputs can be controlled and can be muted individually. The
output pins are at reference DC level when the output is muted.
-10dB or +0dB
-10dB or 0dB
DAC Output
SIDETONE
Output from PGA Boost
MONO
MIXER
SPEAKER
MIXER
SPKOUT+
MOUT
VSSSPK
-1
VDDSPK
SPKBST[2]
(0x31)
SPKOUT-
Zero Cross
Detection
Output from
Auxiliary Amplifier
VSSSPK
VDDSPK
SPKBST
0
1
GAIN
1.0x
1.5x
MOUTBST
0
1
GAIN
1.0x
1.5x
DC output
1.0 x VREF
1.5 x VREF
SPKVOL[5:0]
(0x36)
MOUTBST[3]
(0x31)
SPKMXEN[2]
(0x03)
DACOUT[0]
(0x38)
Zero Cross
Detection
Buffer
DC output
1.0 x VREF
1.5 x VREF
MOUTMXEN[3]
(0x03)
NAU8812
emPowerAudio
™
Datasheet Revision 2.0 Page 37 of 109 January 2011
Bit(s)
Addr
Parameter
Programmable Range
SPKMXEN[2]
0x03
Speaker Mixer enable
0 – Disabled
1 – Enabled
PSPKEN[5]
0x03
Speaker positive terminal
enable
0 – Disabled
1 – Enabled
NSPKEN[6]
0x03
Speaker negative terminal
enable
0 – Disabled
1 – Enabled
SPKATT[1]
0x28
Speaker output attenuation
0 - 0dB
1 - -10dB
SPKBST[2]
0x31
Speaker output Boost
0 – (1.0x VREF) Boost
1- (1.5 x VREF) Boost
SPKGAIN[5:0]
0x36
Speaker output Volume
Range: -57dB to +6dB @ 6dB increment
SPKMT[6]
0x36
Speaker output Mute
0 – Speaker Enabled
1 – Speaker Muted
Table 17: Speaker Output Controls
12.6.2. MONO Mixer Output
The single ended output can drive headphone loads of 16Ω or 32Ω or a line output. The MOUT can be manipulated
by changing attenuation and the volume (loudness of the output signal).
The output stage is powered by the speaker supply, VDDSPK, which are capable of driving up to 1.5VRMS signals.
The MONO output can be enabled for signal output or muted. The output pins are at reference DC level when the
output is muted.
Bit(s)
Addr
Parameter
Programmable Range
MOUTMXEN[3]
0x03
MONO mixer enable
0 – Disabled
1 – Enabled
MOUTEN[7]
0x03
MONO output enable
0 – Disabled
1 – Enabled
MOUTATT[2]
0x28
MONO output attenuation
0 - 0dB
1 - -10dB
MOUTBST[3]
0x31
MONO output boost
0 – (1.0x VREF) Boost
1- (1.5 x VREF) Boost
MOUTMXMT[6]
0x38
MONO Output Mixer Mute
0 – MONO Mixer Normal Mode
1 – MONO Mixer Muted
MOUTMT[4]
0x45
MONO Output Mute
0 – MONO Output Normal Mode
1 – MONO Output Muted
Table 18: MONO Output Controls
NAU8812
emPowerAudio
™
Datasheet Revision 2.0 Page 38 of 109 January 2011
12.6.3. Unused Analog I/O
Figure 20: Tie-off Options for the Speaker and MONO output Pins
In audio and voice systems, any time there is a sudden change in voltage to an audio signal, an audible pop or click
sound may be the result. Systems that change inputs and output configurations dynamically, or which are required to
manage low power operation, need special attention to possible pop and click situations. The NAU8812 includes
many features which may be used to greatly reduce or eliminate pop and click sounds. The most common cause of a
pop or click signal is a sudden change to an input or output voltage. This may happen in either a DC coupled system,
or in an AC coupled system.
The strategy to control pops and clicks is similar for either a DC coupled system, or an AC coupled system. The case
of the AC coupled system is the most common and the more difficult situation, and therefore, the AC coupled case
will be the focus for this information section. When an input or output pin is being used, the DC level of that pin will
be very close to half of the VDDA voltage that is present on the VREF pin. The only exception is that when outputs
are operated in the 5-Volt mode known as the 1.5x boost condition, then the DC level for those outputs will be equal
to 1.5xVREF. In all cases, any input or output capacitors will become charged to the operating voltage of the used
1K
30K
1K
30K
1K
30K
30k
30k
40k
VREF
AUX
MIC-
MIC+
MOUT
SPKOUT+
SPKOUT-
R
R
IOBUFEN[2]
(0x01)
DCBUFEN[8]
(0x01)
AOUTIMP[0]
(0x31)
1.5 x VREF
1.0 x VREF
PMICPGA[0]
(0x2C)
NMICPGA[1]
(0x2C)
AUXEN[6]
(0x01)
MOUTBST[3] = 1
(0x31)
MOUTBST[3] = 0
(0x31)
SPKBST[2] = 0
(0x31)
SPKBST[2] = 1
(0x31)
SMOUT[3]
(0x4F)
SPSPK[4]
(0x4F)
SNSPK[5]
(0x4F)
SBUFH[7]
(0x4F)
SBUFL[6]
(0x4F)
NAU8812
emPowerAudio
™
Datasheet Revision 2.0 Page 39 of 109 January 2011
input or output pin. The goal to reduce pops and clicks is to insure that the charge voltage on these capacitors does
not change suddenly at any time.
When an input or output is in a not-used operating condition, it is desirable to keep the DC voltage on that pin at the
same voltage level as the DC level of the used operating condition. This is accomplished using special internal DC
voltage sources that are at the required DC values. When an input or output is in the not-used condition, it is
connected to the correct internal DC voltage as not to have a pop or click. This type of connection is known as a “tie-
off” condition.
Two internal DC voltage sources are provided for making tie-off connections. One DC level is equal to the VREF
voltage value, and the other DC level is equal to 1.5x the VREF value. All inputs are always tied off to the VREF
voltage value. Outputs will automatically be tied to either the VREF voltage value or to the 1.5xVREF value,
depending on the value of the “boost” control bit for that output. That is to say, when an output is set to the 1.5x gain
condition, then that same output will automatically use the 1.5xVREF value for tie-off in the not-used condition. The
input pull-ups are connected to IOBUFEN[2] address (0x01) buffer with a voltage source (VREF). The output pull-ups
can be connected two different buffers depending on the voltage source. IOBUFEN[2] address (0x01) buffer is
enabled if the voltage source is (VREF) and DCBUFEN[8] address (0x01) buffer is enabled if the voltage source is
(1.5 x VREF). IOBUFEN[2] address (0x01) buffer is shared between input and output pins.
To conserve power, these internal voltage buffers may be enabled/disabled using control register settings. To better
manage pops and clicks, there is a choice of impedance of the tie-off connection for unused outputs. The nominal
values for this choice are 1kΩ and 30kΩ. The low impedance value will better maintain the desired DC level in the
case when there is some leakage on the output capacitor or some DC resistance to ground at the NAU8812 output
pin. A tradeoff in using the low-impedance value is primarily that output capacitors could change more suddenly
during power-on and power-off changes.
Automatic internal logic determines whether an input or output pin is in the used or un-used condition. This logic
function is always active. An output is determined to be in the un-used condition when it is in the disabled unpowered
condition, as determined by the power management registers. An input is determined to be in the un-used condition
when all internal switches connected to that input are in the “open” condition.
12.7. GENERAL PURPOSE I/O
The CSb/GPIO pin can be configured in two ways, chip select for SPI interface and general purpose GPIO.
Therefore, the general-purpose configuration is only available in the 2-Wire interface mode, which is configured by
setting GPIOSEL[2:0] address (0x08) to 001 – 101. “000” configures the pin to be a chip select for SPI mode. The
CSb/GPIO pin is not available in the SPI interface mode. When the pin is configured as an input, it can be used as
chip select signal for SPI interface or for jack detect. When the pin is configured as output, it can be used for
signaling analog mute, temperature alert, PLL frequency output, and PLL frequency lock. The CSb/GPIO pin can
also output the master clock through a PLL or directly. The path also included a divider for different clocks needed in
the system. Note that SCLKEN must be enabled when using the Jack Detect function.
NAU8812
emPowerAudio
™
Datasheet Revision 2.0 Page 40 of 109 January 2011
Addr
D8
D7
D6
D5
D4
D3
D2
D1
D0
Default
0x08
0
0
0
GPIOPLL[1:0]
GPIOPL
GPIOSEL[2:0]
0x000
0x07
0
0
0
0
0
SMPLR[2:0]
SCLKEN
0x000
Table 19: General Purpose Control
12.7.1. Slow Timer Clock
An internal Slow Timer Clock is supplied to automatically control features that happen over a relatively long period of
time, or time-spans. This enables the NAU8812 to implement long time-span features without any host/processor
management or intervention.
The Slow Timer Clock supports two features automatic time out for the zero-crossing holdoff of PGA volume
changes, and timing for debouncing of the mechanical jack detection feature. If either feature is required, the Slow
Timer Clock must be enabled. The Slow Timer Clock is initialized in the disabled state.
The Slow Timer Clock rate is derived from MCLK using an integer divider that is compensated for the sample rate as
indicated by the register address (0x07). If the sample rate register value precisely matches the actual sample rate,
then the internal Slow Timer Clock rate will be a constant value of 128ms. If the actual sample rate is, for example,
44.1kHz and the sample rate selected in register 0x07 is 48kHz, the rate of the Slow Timer Clock will be
approximately 10% slower in direct proportion of the actual vs. indicated sample rate. This scale of difference should
not be important in relation to the dedicated end uses of the Slow Timer Clock.
12.7.2. Jack Detect
Jack detect is a specific GPIO function. Jack detect is only available in 2-Wire mode only. Jack detect is selected by
setting GPIOSEL[2:0] address (0x08) to “001”. The GPIOPL[3] bit address (0x08) inverts the CSb/GPIO pin when set
to 1. The table below shows all the combinations for jack insert detects.
The CSb/GPIO pin has an internal de-bounce circuit so that when the jack detect feature is enabled it does not toggle
multiple times due to input glitches. Slow clock mode must be enabled when using jack insert detect by setting
SCLKEN[0] address (0x07).
GPIOPL
CSb/GPIO
NSPKEN/
PSPKEN
MOUTEN
Speaker
Enabled
MONO output
Enabled
0
0
1
X
Yes
No
0
1
X
1
No
Yes
1
0
X
1
No
Yes
1
1
1
X
Yes
No
Table 20: Jack Insert Detect mode
NAU8812
emPowerAudio
™
Datasheet Revision 2.0 Page 41 of 109 January 2011
Bit(s)
Addr
Parameter
Programmable Range
GPIOSEL[2:0]
0x08
GPIO select
0 - CSb Input
1 - Jack Detect
2 - Temperature OK
3 - AMUTE Active
4 - PLL Frequency Output
5 - PLL Lock (0- Locked, 1 – Not Locked)
6 - HIGH
7 - LOW
GPIOPL[3]
0x08
GPIO polarity
0 – Non- Inverted
1 – Inverted
GPIOPLL[4:5]
0x08
GPIO PLL divider
0 - Divide by 1
1 - Divide by 2
2 - Divide by 3
3 - Divide by 4
PSPKEN[5]
0x03
Speaker positive terminal enable
0 – Muted
1 – Enabled
NSPKEN[6]
0x03
Speaker negative terminal enable
0 – Muted
1 – Enabled
MOUTEN[7]
0x03
MONO Output enable
0 – Muted
1 – Enabled
SCLKEN[0]
0x07
Slow clock enable
Period 221 * MCLK
Table 21: Jack Insert Detect controls
12.7.3. Thermal Shutdown
The device contains an on-chip temperature sensor that senses the temperature inside the package. By enabling the
temperature sensor interrupt in GPIOSEL[2:0] address (0x08), an interrupt will be generated if the temperature
reaches a threshold of approximately 125°C. This facilitates control of the temperature should the device get close to
the junction temperature. Note that there is no filtering associated with this temperature alarm since the package has
an intrinsic thermal time constant. The thermal temperature is enabled by setting TSEN[1] address (0x31).
Bit(s)
Addr
Parameter
Programmable Range
TSEN[1]
0x31
Temperature Sense Enable
0: Thermal Shutdown Disable
1: Thermal Shutdown Enable
Table 22: Thermal Shutdown
NAU8812
emPowerAudio
™
Datasheet Revision 2.0 Page 42 of 109 January 2011
12.8. CLOCK GENERATION BLOCK
Figure 21: PLL and Clock Select Circuit
The NAU8812 has two basic clock modes that support the ADC and DAC data converters. It can accept external
clocks in the slave mode, or in the master mode, it can generate the required clocks from an external reference
frequency using an internal PLL (Phase Locked Loop). The internal PLL is a fractional type scaling PLL, and
therefore, a very wide range of external reference frequencies can be used to create accurate audio sample rates.
Separate from this ADC and DAC clock subsystem, audio data are clocked to and from the NAU8812 by means of
the control logic described in the Digital Audio Interfaces section. The Frame Sync (FS) and Bit Clock (BCLK) pins in
the Digital Audio Interface manage the audio bit rate and audio sample rate for this data flow.
It is important to understand that the Digital Audio Interface does not determine the sampling rate for the ADC and
DAC data converters, and instead, this rate is derived exclusively from the Internal Master Clock (IMCLK). It is
therefore a requirement that the Digital Audio Interface and data converters be operated synchronously, and that the
FS, BCLK, and IMCLK signals are all derived from a common reference frequency. If these three clocks signals are
not synchronous, audio quality will be reduced.
The IMCLK is always exactly 256 times the sampling rate of the data converters. IMCLK is output from the Master
Clock Prescaler. The prescaler reduces by an integer division factor the input frequency input clock. The source of
this input frequency clock is either the external MCLK pin, or the output from the internal PLL Block.
MCLK
f/2
PLL1
R=f2/f1f/4
f1f2
fPLL
f/N
…
GPIO1
/CSb GPIO1PLL[5:4]
(0x08)
PLLMCLK[4]
(0x24)
f/N
MCLKSEL[7:5]
(0x06) f/N
GPIO1SEL[2:0]
(0x08)
CLKIOEN[0]
(0x06) FS
BCLK
BCLKSEL[4:2]
(0x06)
DACOS[3]
(0x0A)
ADCOS[3]
(0x0E)
PLL BLOCK CLKM[8]
(0x06)
IMCLK/
256
IMCLK/
N
ADC
DAC
f/N
Digital Audio
Interface
IMCLK
NAU8812
emPowerAudio
™
Datasheet Revision 2.0 Page 43 of 109 January 2011
Addr
D8
D7
D6
D5
D4
D3
D2
D1
D0
Default
0x01
DCBUFEN
0
AUXEN
PLLEN
MICBIASEN
ABIASEN
IOBUFEN
REFIMP
0x06
CLKM
MCLKSEL[2:0]
BCLKSEL[2:0]
0
CLKIOEN
0x140
0x07
0
0
0
0
0
SMPLR[2:0]
SCLKEN
0x000
0x24
0
0
0
0
PLLMCLK
PLLN[3:0]
0x008
0x25
0
0
0
PLLK[23:18]
0x00C
0x26
PLLK[17:9]
0x093
0x27
PLLK[8:0]
0x0E9
Table 23: Registers associated with PLL
In Master Mode, the IMCLK signal is used to generate FS and BCLK signals that are driven onto the FS and BCLK
pins and input to the Digital Audio Interface. FS is always IMCLK/256 and the duty cycle of FS is automatically
adjusted to be correct for the mode selected in the Digital Audio Interface. The frequency of BCLK may optionally be
divided to optimize the bit clock rate for the application scenario.
In Slave Mode, there is no connection between IMCLK and the FS and BCLK pins. In this mode, FS and BLCK are
strictly input pins, and it is the responsibility of the system designer to insure that FS, BCLK, and IMCLK are
synchronous and scaled appropriately for the application.
12.8.1. Phase Locked Loop (PLL) General description
The PLL may be optionally used to multiply an external input clock reference frequency by a high resolution fractional
number. To enable the use of the widest possible range of external reference clocks, the PLL block includes an
optional divide-by-two prescaler for the input clock, a fixed divide-by-four scaler on the PLL output, and an additional
programmable integer divider that is the Master Clock Prescaler.
The high resolution fraction for the PLL is the ratio of the desired PLL oscillator frequency (f2), and the reference
frequency at the PLL input (f1). This can be represented as R = f2/f1, with R in the form of a decimal number:
xy.abcdefgh. To program the NAU8812, this value is separated into an integer portion (“xy”), and a fractional
portion, “abcdefgh”. The fractional portion of the multiplier is a value that when represented as a 24-bit binary
number (stored in three 9-bit registers on the NAU8812), very closely matches the exact desired multiplier factor.
To keep the PLL within its optimal operating range, the integer portion of the decimal number (“xy”), must be any of
the following decimal values: 6, 7, 8, 9, 10, 11, or 12. The input and output dividers outside of the PLL are often
helpful to scale frequencies as needed to keep the “xy” value within the required range. Also, the optimum PLL
oscillator frequency is in the range between 90MHz and 100MHz, and thus, it is best to keep f2 within this range.
NAU8812
emPowerAudio
™
Datasheet Revision 2.0 Page 44 of 109 January 2011
In summary, for any given design, choose:
Equations
Description
Notes
IMCLK = (256) * (desired codec
sample rate)
IMCLK = desired Master Clock
f2 = (4 * P * IMCLK)
where P is the Master Clock divider
integer value;
optimal f2: 90MHz< f2 <100MHz
The integer values for D and P are
chosen to keep the PLL in its
optimal operating range. It may
be best to assign initial values of 1
to both D and P, and then by
inspection, determine if they
should be a different value.
f1 = (MCLK * D)
where D is the PLL Prescale factor of 1, or
2, and MCLK is the frequency at the
MCLK pin
R = f2 / f1 = xy.abcdefgh decimal
value
which is the fractional frequency
multiplication factor for the PLL
N = xy
truncated integer portion of the R value
and limited to decimal value 6, 7, 8, 9, 10,
11, or 12
K = (224) * (0.abcdefgh)
rounded to the nearest whole integer
value then converted to a binary 24-bit
value
Table 24: Registers associated with PLL
12.8.2. CSB/GPIO as PLL out (fPLL)
CSB/GPIO is a multi-function pin that may be used for a variety of purposes. If not required for some other purpose,
this pin may be configured to output the clock frequency from the PLL subsystem. This is the same frequency that is
available from the PLL subsystem as the input to the Master Clock Prescaler. This frequency may be optionally
divided by an additional integer factor of 2, 3, or 4, before being output on GPIO.
12.8.3. Phase Locked Loop (PLL) Design Example
In an example application, a desired sample rate for the DAC is known to be 48.000kHz. Therefore, it is also known
that the IMCLK rate will be 256fs, or 12.288MHz. Because there is a fixed divide-by-four scaler on the PLL output,
then the desired PLL oscillator output frequency will be 49.152MHz.
In this example system design, there is already an available 12.000MHz clock from the USB subystem. To reduce
system cost, this clock will also be used for audio. Therefore, to use the 12MHz clock for audio, the desired fractional
multiplier ratio would be R = 49.152/12.000 = 4.096. This value, however, does not meet the requirement that the
“xy” whole number portion of the multiplier be in the inclusive range between 6 and 12. To meet the requirement, the
Master Clock Prescaler can be set for an additional divide-by-two factor. This now makes the PLL required oscillator
frequency 98.304 MHz, and the improved multiplier value is now R = 98.304/12.000 = 8.192.
NAU8812
emPowerAudio
™
Datasheet Revision 2.0 Page 45 of 109 January 2011
To complete this portion of the design example, the integer portion of the multiplier is truncated to the value, 8 and
the fractional portion is multiplied by 224, as to create the needed 24-bit binary fractional value. The calculation for
this is: (224)(0.192) = 3221225.472.
It is best to round this value to the nearest whole value of 3221225, or hexadecimal 0x3126E9.
Below are additional examples of results for this calculation applied to commonly available clock frequencies and
desired IMCLK 256fs sample rates.
MCLK
(MHz)
Desired
Output
(MHz)
Input
Frequency
(f1)
f2
(MHz)
MCLK
Divider
bits
R
N
(Hex)
K (Hex)
Actual Register Setting
PLLK[23:18]
PLLK[17:9]
PLLK[8:0]
12.0
11.28960
MCLK/1
90.3168
fPLL/2
7.526400
7
86C226
21
161
26
12.0
12.28800
MCLK/1
98.3040
fPLL/2
8.192000
8
3126E9
0C
93
E9
14.4
11.28960
MCLK/1
90.3168
fPLL/2
6.272000
6
45A1CA
11
D0
1CA
14.4
12.28800
MCLK/1
98.3040
fPLL/2
6.826667
6
D3A06D
34
1D0
6D
19.2
11.28960
MCLK/2
90.3168
fPLL/2
9.408000
9
6872B0
1A
39
B0
19.2
12.28800
MCLK/2
98.3040
fPLL/2
10.240000
10
3D70A3
0F
B8
A3
19.8
11.28960
MCLK/2
90.3168
fPLL/2
9.122909
9
1F76F8
07
1BB
F8
19.8
12.28800
MCLK/2
98.3040
fPLL/2
9.929697
9
EE009E
3B
100
9E
24.0
11.28960
MCLK/2
90.3168
fPLL/2
7.526400
7
86C226
21
161
26
24.0
12.28800
MCLK/2
98.3040
fPLL/2
8.192000
8
3126E9
0C
93
E9
26.0
11.28960
MCLK/2
90.3168
fPLL/2
6.947446
6
F28BD4
3C
145
1D4
26.0
12.28800
MCLK/2
98.3040
fPLL/2
7.561846
7
8FD526
23
1EA
126
Table 25: PLL Frequency Examples
NAU8812
emPowerAudio
™
Datasheet Revision 2.0 Page 46 of 109 January 2011
12.9. CONTROL INTERFACE
The NAU8812 features two serial bus interfaces SPI and 2-Wire that provide access to the control registers. The
MODE pin in conjunction with SPIEN[8] (address 0x49) as shown in the following Table selects the control interfaces.
2-Wire interface is compatible with industry I2C serial bus protocol using a bidirectional data signal (SDIO) and a
clock signal (SCLK). SPI interface is also compatible with other industry interfaces allowing operation on a simple 3-
wire or 4-wire bus. Table below describes the selection of the protocol modes.
MODE Pin
SPIEN[8] Bit
(0x49)
Description
0
0
2-Wire Interface (Write/Read)
1
0
SPI Interface 16-bit (Write ONLY)
x
1
SPI Interface 32-bit (Read)
SPI Interface 24-bit (Write)
(SSOP 28-Pin Write ONLY,
QFN 32-Pin Write/Read)
Table 26: Control Interface Selection
12.9.1. SPI Serial Control
The Serial Peripheral Interface (SPI) is one of the widely accepted communication interfaces implemented in
Nuvoton‟s Audio CODEC portfolio. SPI is a software protocol allowing operation on a simple 3-wire or 4-wire bus
where the data is transferred MSB first. NAU8812 has two different SPI architectures
16-bit write ONLY (default)
24-bit write with 32-bit read
The SPI interface consists of a clock (SCLK), chip select (CSb), serial data input (SDIO), and serial data output (SO)
to configure all the internal register contents. The SO Pin is ONLY available on the 32-Pin QFN package. SCLK is
static, allowing the user to stop the clock and then start it again to resume operations where it left off.
The 24-bit write operation consists of 8-bits of device address, 7-bits of control register address, and 9-bits of data.
The 32-bit read operation consists of 8-bits of device address, 8-bits of control register address, and 16-bits of data of
which 9 LSB bits are actual data bits and the rest are 0‟s.
The device address
Write operation is 00010000b = 10h
Read operation is 00100000b = 20h
NAU8812
emPowerAudio
™
Datasheet Revision 2.0 Page 47 of 109 January 2011
12.9.1.1. 16-bit Write Operation (default)
The default control interface architecture is SPI 16-bit. This interface architecture consists of 7-bits of control register
address, and 9-bits of control register data. The MODE Pin set to “1” (HIGH) selects the SPI 16-bit. In this mode, the
user can only do write operation. The write operation requires a valid control register address, then a valid 9-bit Data
Byte and the finally to complete the transaction the CSb has to transition from LOW to HIGH to latch the last 9-bits
(data).
Control Register
Address 9-bit Data Byte
SDIO
SCLK
CBb/GPIO
A6 A5 A4 A3 A2 A1 A0 D8 D6 D5 D4 D3 D2 D1 D0D7
Figure 22: Register write operation using a 16-bit SPI Interface
12.9.1.2. 24-bit Write Operation
The 24-bit write operation is a three-byte operation. To start the operation the host controller transitions the CSb from
HIGH to LOW. The host micro-controller sends valid device address, then a valid control register address following
Data Byte. Finally the interface is terminated by toggling CSb pin from LOW to HIGH. The write operation will accept
multiple 9-bit DATA blocks, which will be written in to sequential address beginning with the address, specified in the
control register address. Steps below show the procedure to enter and exit SPI 24-bit write and 32-bit read
Procedure to enter the 24-bit SPI interface
Set the Mode pin to “0” (LOW)
Use the 2-wire write architecture to write to register address 0x049 SPIEN[8] = “1” (HIGH)
OR
Set the Mode pin to “1” (HIGH)
Use the 16-bit write architecture to write to register address 0x049 SPIEN[8] = “1” (HIGH)
Procedure to exit the 24-bit SPI interface
Use the 24-bit write architecture to write to register address 0x49 SPIEN[8] = “0” (LOW)
Depending on the state of the Mode pin, control interface will be selected
o Mode Pin = “0” for I2C
o Mode Pin = “1” for 16-bit SPI
NAU8812
emPowerAudio
™
Datasheet Revision 2.0 Page 48 of 109 January 2011
Figure 23: Register Write operation using a 24-bit SPI Interface
12.9.1.3. 32-bit Read Operation
The 32-bit read operation is a four-byte operation with 2-bytes of data. The transmission starts with the falling edge
of the CSb line and ends with the rising edge of the CSb. The host micro-controller sends device address, control
register address byte following 2 bytes of data. The device can receive more than one byte of data by continuously
clocking. Note after reaching the maximum address the internal pointer “rolls over” to address 0x00 (hex). The
device will output a dummy byte [0x00] when locations without register assignments are within the sequence.
Figure 24: Register Read operation through a 32-bit SPI Interface
12.9.2. 2-WIRE Serial Control Mode (I2C Style Interface)
The NAU8812 supports a bidirectional bus oriented protocol. The protocol defines any device that sends data onto
the bus as a transmitter and the receiving device as the receiver. Therefore, the 2-Wire operates as slave interface.
All communication over the 2-Wire interface is conducted by sending the MSB of each byte of data first.
0 0 0 0 0 001
Device Address = 10h Control Register
Address 9-bit Data Byte
SDIO
SCLK
CBb/GPIO
A6 A5 A4 A3 A2 A1 A0 D8 D6 D5 D4 D3 D2 D1 D0D7
CBb/GPIO
0 0 1 0 0 0 00
Device Address = 20h Control Register
Address
SDIO
SCLK
000000
Data Byte 2
SO
Data Byte 1
A5 A4 A3 A2 A1 A0
D8 D6 D5 D4 D3 D2 D1 D0D7
A6 0
0
NAU8812
emPowerAudio
™
Datasheet Revision 2.0 Page 49 of 109 January 2011
12.9.2.1. 2-WIRE Protocol Convention
All 2-Wire interface operations must begin with a START condition, which is a HIGH to LOW transition of SDIO while
SCLK is HIGH. All 2-Wire and all interface operations are terminated by a STOP condition, which is a LOW to HIGH
transition of SDIO while SCLK is HIGH. A STOP condition at the end of a read or write operation places the device in
standby mode. An acknowledge (ACK), is a software convention used to indicate a successful data transfer. The
transmitting device, either master or slave, releases the SDIO bus after transmitting eight bits. During the ninth clock
cycle, the receiver pulls the SDIO line LOW to acknowledge the reception of the eight bits of data.
Following a START condition, the master must output a device address byte. The 7-MSB bits “0011010” are the
device address. The LSB of the device address byte is the R/W bit and defines a read (R/W = 0) or write (R/W = 1)
operation. When this, R/W, bit is a “1”, then a read operation is selected and when “0” the device selects a write
operation. The device outputs an acknowledge LOW for a correct device address and HIGH for an incorrect device
address on the SDIO pin.
SCLK
SDIO
START
Figure 25: Valid START Condition
SCLK
SDIO
Receive
SDIO
Transmit
ACK
9th
Clock
Figure 26: Valid Acknowledge
STOP
SCLK
SDIO
Figure 27: Valid STOP Condition
Figure 28: Slave Address Byte, Control Address Byte, and Data Byte
12.9.2.2. 2-WIRE Write Operation
A Write operation consists of a two-byte instruction followed by one or more Data Bytes. A Write operation requires a
START condition, followed by a valid device address byte, a valid control address byte, data byte(s), and a STOP
condition. After each three bytes sequence, the NAU8812 responds with an ACK and the 2-Wire interface enters a
standby state.
Device
Address Byte
Control
Address Byte
Data Byte
0 0 1 1 0 1 0 R/W
D7 D6 D5 D4 D3 D2 D1 D0
A6 A5 A4 A3 A2 A1 A0 Write - D8
Read - 0
NAU8812
emPowerAudio
™
Datasheet Revision 2.0 Page 50 of 109 January 2011
Figure 29: Byte Write Sequence
12.9.2.3. 2-WIRE Read Operation
A Read operation consists of a three-byte instruction followed by one or more Data Bytes. The master initiates the
operation issuing the following sequence: a START condition, device address byte with the R/W bit set to “0”, a
control address byte, a second START condition, and a second device address byte with the R/W bit set to “1”.
After each of the three bytes, the NAU8812 responds with an ACK. Then the NAU8812 transmits Data Bytes as long
as the master responds with an ACK during the SCLK cycle following the ninth bit of each byte. The master
terminates the read operation (issuing a STOP condition) following the last bit of the last Data Byte.
After reaching the memory location 7Fh the pointer “rolls over” to 00h, and the device continues to output data for
each ACK received.
Figure 30: 2-Wire Read Sequence
0 0 0 0 0
1
Device Address = 34h Control Register Address 9-bit Data Byte
SDIO
SCLK
A6 A5 A4 A3 A2 A1 A0 D8 D6 D5 D4 D3 D2 D1 D0
D7
1 1
A
C
K
A
C
K
S
T
A
R
T
S
T
O
P
A
C
K
SDIO 0 0 0 0 0
1
Device Address = 34h Control Register Address 2ND Device Address = 35h
SCLK
A6 A5 A4 A3 A2 A1 A0 0
000000D8
0
1 1
A
C
K
S
T
A
R
T
S
T
O
P
A
C
K
16-bit Data
0110101
0
A
C
K
S
T
A
R
T
D6 D5 D4 D3 D2 D1 D0
D
7
A
C
K
A
C
K
NAU8812
emPowerAudio
™
Datasheet Revision 2.0 Page 51 of 109 January 2011
12.10. DIGITAL AUDIO INTERFACES
NAU8812 only uses the Left channel to transfer data in normal mode. It supports an independent digital interface for
voice and audio. The digital interface is used to input digital data to the DAC, or output digital data from the ADC.
The digital interface can be configured to Master mode or Slave mode.
Master mode is configured by setting CLKIOEN[0] address (0x06) bit to HIGH. The main clock (MCLK) of the digital
interface is provided from an external clock either from a crystal oscillator or from a microcontroller. With an
appropriate MCLK, the device generates bit clock (BCLK) and frame sync (FS) internally in the master mode. By
generating the bit clock and frame sync internally, the NAU8812 has full control of the data transfer.
Slave mode is configured by setting CLKIOEN[0] address (0x06) bit to LOW. In this mode, an external controller has
to supply the bit clock and the frame sync. The NAU8812 uses ADCOUT, DACIN, FS, and BCLK pins to control the
digital interface. Care needs to be exercised when designing a system to operate the NAU8812 in this mode as the
relationship between the sample rate, bit clock, and frame sync needs to be controlled by other controller. In both
modes of operation, the internal MCLK and MCLK prescalers determine the sample rate for the DAC and ADC.
The output state of the ADCOUT pin by default is pulled-low. Depending on the application, the output can be
configured to be Hi-Z, pull-low, pull-high, Low or High. To configure the output, three different bits have to be set.
First the output switched to the mask by setting PUDOEN[5] address (0x3C), then the mask has to be enabled be
setting PUDPE[4] address (0x3C) and finally output state select pulled up or down by PUDPS[3] address (0x3C). Six
different audio formats are supported by NAU8812 with MSB first and they are as follows.
AIFMT[4]
Addr: (0x04)
AIFMT[3]
Addr: (0x04)
PCMTSEN[8]
Addr: (0x3C)
PCMB[1]
Addr: (0x3C)
PCM Mode
0
0
0
1
PCM B
0
0
0
0
Right Justified
0
1
0
0
Left Justified
1
0
0
0
I2S
1
1
0
0
PCM A
1
1
1
0
PCM Time Slot
Table 27: Standard Interface modes
Addr
D8
D7
D6
D5
D4
D3
D2
D1
D0
Default
0x04
BCLKP
FSP
WLEN[1:0]
AIFMT[1:0]
DACPHS
ADCPHS
0
0x050
0x06
CLKM
MCLKSEL[2:0]
BCLKSEL[2:0]
0
CLKIOEN
0x140
0x3B
TSLOT[8:0]
0x000
0x3C
PCMTSEN
TRI
PCM8BIT
PUDOEN
PUDPE
PUDPS
LOUTR
PCMB
TSLOT[9:8]
0x000
Table 28: Audio Interface Control Registers
NAU8812
emPowerAudio
™
Datasheet Revision 2.0 Page 52 of 109 January 2011
12.10.1. Right Justified audio data
In right justified interface (normal mode), the left channel serial audio data is synchronized with the frame sync. Left
channel data is transferred during the HIGH frame sync. The MSB data is sampled first. The data is latched on the
last rising edge of BCLK before frame sync transition (FS). The LSB is aligned with the falling edge of the frame sync
signal (FS). Right justified format is selected by setting AIFMT[1:0] address (0x04) to “00” binary in conjunction with
PCMTSEN[8] address (0x3C) set to LOW.
Figure 31: Right Justified Audio Interface (Normal Mode)
NAU8812 features a special mode where the device outputs Left channel data to both Left and Right channels. This
is accomplished by setting LOUTR[2] address (0x3C) to “1”
Figure 32: Right Justified Audio Interface (Special mode)
LEFT CHANNEL RIGHT CHANNELFS
N-1 N1 2
MSB LSB
DACIN/
ADCOUT
BCLK
LEFT CHANNEL RIGHT CHANNELFS
N-1 N1 2
MSB LSB
ADCOUT
BCLK
N-1 N1 2
MSB LSB
NAU8812
emPowerAudio
™
Datasheet Revision 2.0 Page 53 of 109 January 2011
12.10.2. Left Justified audio data
In Left justified interface (normal mode), the left channel serial audio data is synchronized with the frame sync. Left
channel data is transferred during the HIGH frame sync. The MSB data is sampled first and is available on the first
rising edge of BCLK following a frame sync transition (FS). Left justified format is selected by setting AIFMT[1:0]
address (0x04) to “01” binary in conjunction with PCMTSEN[8] address (0x3C) set to LOW.
Figure 33: Left Justified Audio Interface (Normal Mode)
NAU8812 features a special mode where the device outputs Left channel data to both Left and Right channels. This
is accomplished by setting LOUTR[2] address (0x3C) to “1”
Figure 34: Left Justified Audio Interface (Special mode)
LEFT CHANNEL RIGHT CHANNELFS
N-1 N1 2
MSB LSB
DACIN/
ADCOUT
BCLK
LEFT CHANNEL RIGHT CHANNELFS
N-1 N1 2
MSB LSB
ADCOUT
BCLK
N-1 N1 2
MSB LSB
NAU8812
emPowerAudio
™
Datasheet Revision 2.0 Page 54 of 109 January 2011
12.10.3. I2S audio data
In I2S interface (normal mode), the left channel serial audio data is synchronized with the frame sync. Left channel
data is transferred during the LOW frame sync. The MSB data is sampled first. The data is latched on the second
rising edge of BCLK following a frame sync transition (FS). I2S format is selected by setting AIFMT[1:0] address
(0x04) to “10” binary in conjunction with PCMTSEN[8] address (0x3C) set to LOW.
Figure 35: I2S Audio Interface (Normal Mode)
NAU8812 features a special mode where the device outputs Left channel data to both Left and Right channels. This
is accomplished by setting LOUTR[2] address (0x3C) to “1”
Figure 36: I2S Audio Interface (Special mode)
LEFT CHANNEL RIGHT CHANNEL
FS
N-1 N1 2
MSB LSB
DACIN/
ADCOUT
BCLK
1 BCLK
LEFT CHANNEL RIGHT CHANNEL
FS
N-1 N1 2
MSB LSB
ADCOUT
BCLK
1 BCLK
N-1 N1 2
MSB LSB
1 BCLK
NAU8812
emPowerAudio
™
Datasheet Revision 2.0 Page 55 of 109 January 2011
12.10.4. PCM audio data
In PCM interface (normal mode), the left channel serial audio data is synchronized with the frame sync. Left channel
data is transferred during the LOW frame sync. The MSB data is sampled first. The data is latched on the second
rising edge of BCLK following a frame sync transition (FS). PCM format is selected by setting AIFMT[4:3] address
(0x04) to “11” binary in conjunction with PCMTSEN[8] address (0x3C) set to LOW.
The digital data can be forced to appear on the right phase of the FS by setting ADCPHS[0] and DACPHS[1]
address (0x04) bits to HIGH respectively. The starting point of the right phase data depends on the word length
WLEN[6:5] address (0x04) after the frame sync transition (FS).
Figure 37: PCM Mode Audio Interface (Normal Mode)
NAU8812 features a special mode where the device outputs Left channel data to both Left and Right channels. This
is accomplished by setting LOUTR[2] address (0x3C) to “1”
Figure 38: PCM Mode Audio Interface (Special mode)
LEFT CHANNEL
FS
N-1 N1 2
MSB LSB
DACIN/
ADCOUT
BCLK
1 BCLK
Word Length, WLEN[6:5]
LEFT CHANNEL
FS
N-1 N1 2
MSB LSB
ADCOUT
BCLK
1 BCLK
Word Length, WLEN[6:5]
N-1 N1 2
MSB LSB
Word Length, WLEN[6:5]
RIGHT CHANNEL
NAU8812
emPowerAudio
™
Datasheet Revision 2.0 Page 56 of 109 January 2011
12.10.5. PCM Time Slot audio data
In PCM Time-Slot interface (normal mode), the left channel serial audio data is synchronized with the frame sync.
Left channel data is transferred during the LOW frame sync. The MSB data is sampled first. The starting point of the
timeslot is controlled by a 10-bit byte TSLOT[9:0] address (0x3B and 0x3C). The data is latched on the first rising
edge of BCLK following a frame sync transition (FS) providing PCM is in timeslot zero (TSLOT[9:0] = 000). PCM
Time-Slot format is selected by setting AIFMT[4:3] address (0x04) to “11” binary in conjunction with PCMTSEN[8]
address (0x3C) set to HIGH. The digital data can be forced to appear on the right phase of the FS by setting
ADCPHS[0] and DACPHS[1] address (0x04) bits to HIGH respectively. The starting point of the right phase data
depends on the word length WLEN[6:5] address (0x04) and timeslot assignment TSLOT[9:0] address (0x3B and
0x3C) after the frame sync transition (FS). DACIN will return to the bus condition either on the negative edge of
BCLK during the LSB, or on the positive edge of BCLK following the LSB depending on the setting of TRI[7] address
(0x3C). Tri-stating on the negative edge allows the transmission of data by multiple sources in adjacent timeslots
without the risk of driver contention.
Figure 39: PCM Time Slot Mode (Time slot = 0) (Normal Mode)
NAU8812 features a special mode where the device outputs Left channel data to both Left and Right channels. This
is accomplished by setting LOUTR[2] address (0x3C) to “1”
Figure 40: PCM Time Slot Mode (Time slot = 0) (Special mode)
LEFT CHANNEL
FS
N-1 N1 2
MSB LSB
DACIN/
ADCOUT
BCLK
1 BCLK
Word Length, WLEN[6:5]
LEFT CHANNEL
FS
N-1 N1 2
MSB LSB
ADCOUT
BCLK
1 BCLK
Word Length, WLEN[6:5]
N-1 N1 2
MSB LSB
Word Length, WLEN[6:5]
RIGHT CHANNEL
NAU8812
emPowerAudio
™
Datasheet Revision 2.0 Page 57 of 109 January 2011
12.10.6. Companding
Companding is used in digital communication systems to optimize signal-to-noise ratios with reduced data bit rates,
and make use of non-linear algorithms. NAU8812 supports two different types of companding A-law and µ-law on
both transmit and receive sides. A-law algorithm is used in European communication systems and µ-law algorithm is
used by North America, Japan, and Australia. This feature is enabled by setting DACCM[4:3] address (0x05) or
ADCCM[2:1] address (0x05) register bits. Companding converts 13 bits (µ-law) or 12 bits (A-law) to 8 bits using non-
linear quantization. The companded signal is an 8-bit word containing sign (1-bit), exponent (3-bits) and mantissa (4-
bits). As recommended by the G.711 standard (all 8-bits are inverted for µ-law, all even data bits are inverted for A-
law).
Setting CMB8[5] address 0x05 to 1 will cause the PCM interface to use 8-bit word length for data transfer, overriding
the word length configuration setting in WLEN[6:5] address 0x04.
Addr
D8
D7
D6
D5
D4
D3
D2
D1
D0
Default
0x05
0
0
0
CMB8
DACCM[1:0]
ADCCM[1:0]
ADDAP
0x000
Table 29: Companding Control
The following equations for data compression (as set out by ITU-T G.711 standard):
µ-law (where µ=255 for the U.S. and Japan):
F(x) = ln( 1 + µ|x|) / ln( 1 + µ) -1 ≤ x ≤ 1
A-law (where A=87.6 for Europe):
F(x) = A|x| / ( 1 + lnA) for x ≤ 1/A
F(x) = ( 1 + lnA|x|) / (1 + lnA) for 1/A ≤ x ≤ 1
NAU8812
emPowerAudio
™
Datasheet Revision 2.0 Page 58 of 109 January 2011
12.11. POWER SUPPLY
This device has been designed to operate reliably using a wide range of power supply conditions and power-
on/power-off sequences. There are no special requirements for the sequence or rate at which the various power
supply pins change. Any supply can rise or fall at any time without harm to the device. However, pops and clicks
may result from some sequences. Optimum handling of hardware and software power-on and power-off sequencing
is described in more detail in the Power Up/Down Sequencing section of this document.
12.11.1. Power-On Reset
The NAU8812 does not have an external reset pin. The device reset function is automatically generated internally
when power supplies are too low for reliable operation. The internal reset is generated any time that either VDDA or
VDDC is lower than is required for reliable maintenance of internal logic conditions. The threshold voltage for VDDA
is approximately ~1.52Vdc and the threshold voltage for VDDC is approximately ~0.67Vdc. Note that these are much
lower voltages than are required for normal operation of the chip. These values are mentioned here as general
guidance as to overall system design.
If either VDDA or VDDC is below its respective threshold voltage, an internal reset condition may be asserted.
During this time, all registers and controls are set to the hardware determined initial conditions. Software access
during this time will be ignored, and any expected actions from software activity will be invalid.
When both VDDA and VDDC reach a value above their respective thresholds, an internal reset pulse is generated
which extends the reset condition for an additional time. The duration of this extended reset time is approximately 50
microseconds, but not longer than 100 microseconds. The reset condition remains asserted during this time. If either
VDDA or VDDC at any time becomes lower than its respective threshold voltage, a new reset condition will result.
The reset condition will continue until both VDDA and VDDC again higher than their respective thresholds. After
VDDA and VDDC are again both greater than their respective threshold voltage, a new reset pulse will be generated,
which again will extend the reset condition for not longer than an additional 100 microseconds.
12.11.2. Power Related Software Considerations
There is no direct way for software to determine that the device is actively held in a reset condition. If there is a
possibility that software could be accessing the device sooner than 100 microseconds after the VDDA and VDDC
supplies are valid, the reset condition can be determined indirectly. This is accomplished by writing a value to any
register other than register 0x00, with that value being different than the power-on reset initial values. The optimum
choice of register for this purpose may be dependent on the system design, and it is recommended the system
engineer choose the register and register test bit for this purpose. After writing the value, software will then read back
the same register. When the register test bit reads back as the new value, instead of the power-on reset initial value,
software can reliably determine that the reset condition has ended.
NAU8812
emPowerAudio
™
Datasheet Revision 2.0 Page 59 of 109 January 2011
Although it is not required, it is strongly recommended that a Software Reset command should be issued after power-
on and after the power-on-reset condition is ended. This will help insure reliable operation under every power
sequencing condition that could occur.
12.11.3. Software Reset
The control registers can be reset to default conditions by writing any value to RST address (0x00), using any of the
control interface modes. Writing valid data to any other register disables the reset, but all registers will need to be
initiated again appropriate to the operation. See the applications section on powering NAU8812 up for information on
avoiding pops and clicks after a software reset.
12.11.4. Power Up/Down Sequencing
Most audio products have issues during power up and power down in the form of pop and click noise. To avoid cuch
issues the NAU8812 provides four different power supplies VDDA, VDDB, VDDC and VDDSPK with separated
grounds VSSA, VSSD and VSSSPK. The audio CODEC circuitry, the input amplifiers, output amplifiers and drivers,
the audio ADC and DAC converters, the PLL, and so on, can be powered up and down individually by software
control via 2-Wire or SPI interface. The zero cross function should be used when changing the volume in the PGAs
to avoid any audible pops or clicks. There are two different modes of operation 5.0V and 3.3V mode. The
recommended power-up and power-down sequences for both the modes are outlined as following.
Power Up
Name
VDDSPK - 3.3V operation
VDDSPK - 5.0V operation
Power supplies
Analog – VDDA
Analog – VDDA
Buffer - VDDB
Buffer - VDDB
Digital – VDDC
Digital – VDDC
Output driver - VDDSPK
Output driver – VDDSPK
Mode
SPKBST[2] = 0
SPKBST[2] = 1
MOUTBST[3] = 0
MOUTBST[3] = 1
Power
Management
REFIMP[1:0]
as required (value of the REFIMP bits based on the startup time
which is a combination of the reference impedance and the
decoupling capacitor on VREF)
ABIASEN[3] = 1
(enables the internal device bias for all analog blocks)
IOBUFEN[2] = 1
(enables the internal device bias buffer)
Clock divider
CLKIOEN[0] if required
CLKIOEN[0] if required
BCLKSEL[4:2] if required
BCLKSEL[4:2] if required
MCLKSEL[7:5] if required
MCLKSEL[7:5] if required
PLL
PLLEN[5] if required
PLLEN[5] if required
DAC, ADC
DACEN[0] = 1
DACEN[0] = 1
ADCEN[0] = 1
ADCEN[0] = 1
Mixers
SPKMXEN[2]
SPKMXEN[2]
NAU8812
emPowerAudio
™
Datasheet Revision 2.0 Page 60 of 109 January 2011
Power Up
Name
VDDSPK - 3.3V operation
VDDSPK - 5.0V operation
MOUTMXEN[3]
MOUTMXEN[3]
Output stages
MOUTEN[7]
MOUTEN[7]
NSPKEN[6]
NSPKEN[6]
PSPKEN[5]
PSPKEN[5]
Un-mute DAC
DACMT[6] = 0
DACMT[6] = 0
Table 30: Power up sequence
Name
Power Down Both Cases
Un-mute DAC
DACMT[6] = 1
Power Management
PWRM1 = 0x000
Output stages
MOUTEN[7]
NSPKEN[6]
PSPKEN[5]
Power supplies
Analog – VDDA
Buffer - VDDB
Digital – VDDC
Output driver – VDDSPK
Table 31: Power down Sequence
12.11.5. Reference Impedance (REFIMP) and Analog Bias
Before the device is functional or any of the individual analog blocks are enabled REFIMP[1:0] address (0x01) and
ABIASEN[3] address (0x01) must be set. The REFIMP[1:0] bits control the resistor values (“R” in Figure3) that
generates the mid supply reference, VREF. REFIMP[1:0] bits control the power up ramp rate in conjunction with the
external decoupling capacitor. A small value of “R” allows fast ramp up of the mid supply reference and a large value
of “R” provides higher PSRR of the mid supply reference.
The master analog biasing of the device is enabled by setting ABIASEN[3] address (0x01). This bit has to be set
before for the device to function.
12.11.6. Power Saving
Saving power is one of the critical features in a semiconductor device specially ones used in the Bluetooth headsets
and handheld device. NAU8812 has two oversampling rates 64x and 128x. The default mode of operation for the
DAC and ADC is in 64x oversampling mode which is set by programming DACOS[3] address (0x0A) and ADCOS[3]
address (0x0E) respectively to LOW. Power is saved by choosing 64x oversampling rate compared to 128x
NAU8812
emPowerAudio
™
Datasheet Revision 2.0 Page 61 of 109 January 2011
oversampling rate but slightly degrades the noise performance. To each lowest power possible after the device is
functioning set ABIASEN[3] address (0x01) bit to LOW.
Addr
D8
D7
D6
D5
D4
D3
D2
D1
D0
Default
0x01
DCBUFEN
0
AUXEN
PLLEN
MICBIASEN
ABIASEN
IOBUFEN
REFIMP
0x000
0x0A
0
0
DACMT
DEEMP[1:0]
DACOS
AUTOMT
0
DACPL
0x000
0x0E
MOUTFEN
MOUTFAM
MOUTF[2:0]
ADCOS
0
0
ADCPL
0x100
0x3A
LPSPKA
LPIPBST
LPADC
LPSPKD
LPDAC
TRIMREG
0
IBADJ
0
0x000
Table 32: Registers associated with Power Saving
12.11.7. Estimated Supply Currents
NAU8812 can be programmed to enable or disable various analog blocks individually. The table below shows the
amount of current consumed by certain analog blocks. Sample rate settings will vary current consumption of the
VDDC supply. VDDC consumes approximately 4mA with VDDC = 1.8V and fs = 48kHz. Lower sampling rates will
draw lower current.
BIT
Address
VDDA CURRENT
REFIMP[1:0]
0x01
10K => 300 uA
161k/595k < 100 uA
IOBUFEN[2]
40uA
ABIASEN[3]
600uA
MICBIASEN[4]
500 uA
PLLEN[5]
2.5mA Clocks Applied
DCBUFEN[8]
80uA
ADCEN[0]
0x02
x64 - ADCOS= 0 => 2.0mA
x128 - ADCOS= 1 => 3.0mA
PGAEN[2]
400uA
BSTEN[4]
200 uA
DACEN[0]
0x03
X64 (DACOS=0)=>1.6mA
x128(DACOS=1)=>1.7mA
SPKMXEN[2]
400uA
MOUTMXEN[3]
200uA
NSPKEN[6]
1mA from VDDSPK + 100uA (VDDA = 5V mode)
PSPKEN[5]
1mA from VDDSPK + 100uA (VDDA = 5V mode)
MOUTEN[7]
100uA
Table 33: VDDA 3.3V Supply Current
NAU8812
emPowerAudio
™
Datasheet Revision 2.0 Page 62 of 109 January 2011
13. REGISTER DESCRIPTION
Register
Address
Register Names
Register Bits
Default
DEC
HEX
D8
D7
D6
D5
D4
D3
D2
D1
D0
0
0
Software Reset
RESET (SOFTWARE)
000
POWER MANAGEMENT
1
01
Power Management 1
DCBUFEN
0
AUXEN
PLLEN
MICBIASEN
ABIASEN
IOBUFEN
REFIMP
000
2
02
Power Management 2
0
0
0
0
BSTEN
0
PGAEN
0
ADCEN
000
3
03
Power Management 3
0
MOUTEN
NSPKEN
PSPKEN
0
MOUTMXEN
SPKMXEN
0
DACEN
000
AUDIO CONTROL
4
04
Audio Interface
BCLKP
FSP
WLEN[1:0]
AIFMT[1:0]
DACPHS
ADCPHS
0
050
5
05
Companding
0
0
0
0
DACCM[1:0]
ADCCM[1:0]
ADDAP
000
6
06
Clock Control 1
CLKM
MCLKSEL[2:0]
BCLKSEL[2:0]
0
CLKIOEN
140
7
07
Clock Control 2
0
0
0
0
0
SMPLR[2:0]
SCLKEN
000
8
08
GPIO CTRL
0
0
0
GPIOPLL[1:0]
GPIOPL
GPIOSEL[2:0]
000
10
0A
DAC CTRL
0
0
DACMT
DEEMP[1:0]
DACOS
AUTOMT
0
DACPL
000
11
0B
DAC Volume
0
DACGAIN
0FF
14
0E
ADC CTRL
HPFEN
HPFAM
HPF[2:0]
ADCOS
0
0
ADCPL
100
15
0F
ADC Volume
0
ADCGAIN
0FF
DIGITAL TO ANALOG (DAC) LIMITER
24
18
DAC Limiter 1
DACLIMEN
DACLIMDCY[3:0]
DACLIMATK[3:0]
032
25
19
DAC Limiter 2
0
0
DACLIMTHL[2:0]
DACLIMBST[3:0]
000
NOTCH FILTER
27
1B
Notch Filter High
NFCU
NFCEN
NFCA0[13:7]
000
28
1C
Notch Filter Low
NFCU
0
NFCA0[6:0]
000
29
1D
Notch Filter High
NFCU
0
NFCA1[13:7]
000
30
1E
Notch Filter Low
NFCU
0
NFCA1[6:0]
000
ALC CONTROL
32
20
ALC CTRL 1
ALCEN
0
0
ALCMXGAIN[2:0]
ALCMNGAIN[2:0]
038
33
21
ALC CTRL 2
ALCZC
ALCHT[3:0]
ALCSL[3:0]
00B
34
22
ALC CTRL 3
ALCM
ALCDCY[3:0]
ALCATK[3:0]
032
35
23
Noise Gate
0
0
0
0
0
ALCNEN
ALCNTH[2:0]
000
PLL CONTROL
36
24
PLL N CTRL
0
0
0
0
PLLMCLK
PLLN[3:0]
008
37
25
PLL K 1
0
0
0
PLLK[23:18]
00C
38
26
PLL K 2
PLLK[17:9]
093
39
27
PLL K 3
PLLK[8:0]
0E9
INPUT, OUTPUT & MIXER CONTROL
40
28
Attenuation CTRL
0
0
0
0
0
0
MOUTATT
SPKATT
0
000
44
2C
Input CTRL
MICBIASV
0
0
0
AUXM
AUXPGA
NMICPGA
PMICPGA
003
NAU8812
emPowerAudio
™
Datasheet Revision 2.0 Page 63 of 109 January 2011
Register
Address
Register Names
Register Bits
Default
DEC
HEX
D8
D7
D6
D5
D4
D3
D2
D1
D0
45
2D
PGA Gain
0
PGAZC
PGAMT
PGAGAIN[5:0]
010
47
2F
ADC Boost
PGABST
0
PMICBSTGAIN
0
AUXBSTGAIN
100
49
31
Output CTRL
0
0
0
0
0
MOUTBST
SPKBST
TSEN
AOUTIMP
002
50
32
Mixer CTRL
0
0
0
AUXSPK
0
0
0
BYPSPK
DACSPK
001
54
36
SPKOUT Volume
0
SPKZC
SPKMT
SPKGAIN[5:0]
039
56
38
MONO Mixer Control
0
0
MOUTMT
0
0
0
AUXMOUT
BYPMOUT
DACMOUT
001
LOW POWER CONTROL
58
3A
Power Management 4
LPIPBST
LPADC
LPSPKD
LPDAC
MICBIASM
TRIMREG
IBADJ
000
PCM TIME SLOT & ADCOUT IMPEDANCE OPTION CONTROL
59
3B
Time Slot
TSLOT[8:0]
000
60
3C
ADCOUT Drive
PCMTSEN
TRI
PCM8BIT
PUDOEN
PUDPE
PUDPS
LOUTR
PCMB
TSLOT[9:8]
020
REGISTER ID
62
3E
Silicon Revision
0
1
1
1
0
1
1
1
1
0EF
63
3F
2-Wire ID
0
0
0
0
1
1
0
1
0
01A
64
40
Additional ID
0
1
1
0
0
1
0
1
0
0CA
65
41
Reserved
1
0
0
1
0
0
1
0
0
124
69
45
High Voltage CTRL
0
0
0
0
MOUTMT
0
HVOPU
0
HVOP
001
70
46
ALC Enhancements 1
0
ALCPKSEL
ALCNGSEL
ALCGAINL (READ ONLY)
000
71
47
ALC Enhancements 2
PKLIMEN
0
000
73
49
Additional IF CTRL
SPIEN
FSERRVAL[1:0]
FSERFLSH
FSERRENA
NFDLY
DACINMT
PLLLOCKP
DACOS256
000
75
4B
Power/Tie-off CTRL
0
LPSPKA
0
0
0
0
MANVREFH
MANVREFM
MANVREFL
000
76
4C
ALC P2P Detector
P2PDET (READ ONLY)
000
77
4D
ALC Peak Detector
PDET (READ ONLY)
000
78
4E
Control and Status
0
0
AMTCTRL
HVDET
NSGATE
AMUTE
DMUTE
0
FTDEC
000
79
4F
Output tie-off CTRL
MANOUTEN
SBUFH
SBUFL
SNSPK
SPSPK
SMOUT
0
0
0
000
NAU8812
emPowerAudio
™
Datasheet Revision 2.0 Page 64 of 109 January 2011
13.1. SOFTWARE RESET
Addr
D8
D7
D6
D5
D4
D3
D2
D1
D0
Default
0x00
RESET (SOFTWARE)
0x000
This is device Reset register. Performing a write instruction to this register with any data will reset all the bits in the
register map to default.
13.2. POWER MANAGEMENT REGISTERS
13.2.1. Power Management 1
Addr
D8
D7
D6
D5
D4
D3
D2
D1
D0
Default
0x01
DCBUFEN
0
AUXEN
PLLEN
MICBIASEN
ABIASEN
IOBUFEN
REFIMP[1:0]
0x000
Name
Buffer for DC
level shifting
Enable
AUX input
buffer enable
PLL enable
Microphone
Bias
Enable
Analogue
amplifier
bias control
Unused
input/output tie off
buffer enable
Bit
DCBUFEN[8]
AUXEN[6]
PLLEN[5]
MICBIASEN[4]
ABIASEN[3]
IOBUFEN[2]
0
Disable
Disable
Disable
Disable
Disable
Disable
1
Enable
(required for
1.5x gain)
Enable
Enable
Enable
Enable
Enable
The DCBUFEN[8] address (0x01) is a dedicated buffer for DC level shifting output stages when in 1.5x gain boost
configuration. There are three different reference impedance selections to choose from as follows:
VREF REFERENCE
IMPEDANCE SELECTION
(“R” refers to “R” as shown in Figure3)
REFIMP[1]
REFIMP[0]
Mode
0
0
Disable
0
1
R = 80 k
1
0
R = 300 k
1
1
R = 3 k
NAU8812
emPowerAudio
™
Datasheet Revision 2.0 Page 65 of 109 January 2011
13.2.2. Power Management 2
Addr
D8
D7
D6
D5
D4
D3
D2
D1
D0
Default
0x02
0
0
0
0
BSTEN
0
PGAEN
0
ADCEN
0x000
Name
Input Boost
Enable
MIC(+/-)
PGA Enable
ADC Enable
Bit
BSTEN[4]
PGAEN[2]
ADCEN[0]
0
Stage Disable
Disable
Disable
1
Stage Enable
Enable
Enable
13.2.3. Power Management 3
Addr
D8
D7
D6
D5
D4
D3
D2
D1
D0
Default
0x03
0
MOUTEN
NSPKEN
PSPKEN
0
MOUTMXEN
SPKMXEN
0
DACEN
0x000
Name
MOUT
Enable
SPKOUT-
Enable
SPKOUT+
Enable
MONO Mixer
Enable
Speaker Mixer
Enable
DAC
Enable
Bit
MOUTEN[7]
NSPKEN[6]
PSPKEN[5]
MOUTMXEN[3]
SPKMXEN[2]
DACEN[0]
0
Disable
Disable
Disable
Disable
Disable
Disable
1
Enable
Enable
Enable
Enable
Enable
Enable
13.3. AUDIO CONTROL REGISTERS
13.3.1. Audio Interface Control
Addr
D8
D7
D6
D5
D4
D3
D2
D1
D0
Default
0x04
BCLKP
FSP
WLEN[1:0]
AIFMT[1:0]
DACPHS
ADCPHS
0
0x050
The following table explains the PCM control register bits.
Name
BCLK
Polarity
Frame Clock
Polarity
DAC Data „right‟ or „left‟
phases of FRAME clock
ADC Data „right‟ or „left‟
phases of FRAME clock
Bit
BCLKP[8]
FSP[7]
DACPHS[2]
ADCPHS[1]
0
Normal
Normal
DAC data appear in „left‟ phase of
FRAME
ADC data appear in „left‟ phase of
FRAME
1
Inverted
Inverted
DAC data appears in „right‟ phase of
FRAME
ADC data appears in „right‟ phase of
FRAME
There are three different CODEC modes to choose from as follows:
NAU8812
emPowerAudio
™
Datasheet Revision 2.0 Page 66 of 109 January 2011
Word Length Selection
Audio Data Format Select
WLEN[6]
WLEN[5]
Bits
AIFMT[4]
AIFMT[3]
Format
0
0
16
0
0
Right Justified
0
1
20
0
1
Left Justified
1
0
24
1
0
I2S
1
1
32
1
1
PCM A
13.3.2. Audio Interface Companding Control
Addr
D8
D7
D6
D5
D4
D3
D2
D1
D0
Default
0x05
0
0
0
CMB8
DACCM[1:0]
ADCCM[1:0]
ADDAP
0x000
The NAU8812 provides a Digital Loopback ADDAP[0] address (0x05) bit. Setting ADDAP[0] bit to HIGH enables the
loopback so that the ADC data can be fed directly into the DAC input.
Companding Mode 8-bit
word enable
DAC Companding Selection
ADC Companding Select
CMB8[5]
Mode
DACCM[4]
DACCM[3]
Mode
ADCCM[2]
ADCCM[1]
Mode
0
normal operation
0
0
Disabled
0
0
Disabled
1
8-bit operation
0
1
Reserved
0
1
Reserved
1
0
µ-Law
1
0
µ-Law
1
1
A-Law
1
1
A-Law
DAC audio data input option to route
directly to ADC data stream
ADDAP[0]
Mode
0
Normal Operation
1
ADC output data stream
routed to DAC input data
path
NAU8812
emPowerAudio
™
Datasheet Revision 2.0 Page 67 of 109 January 2011
13.3.3. Clock Control Register
Addr
D8
D7
D6
D5
D4
D3
D2
D1
D0
Default
0x06
CLKM
MCLKSEL[2:0]
BCLKSEL[2:0]
0
CLKIOEN
0x140
Master Clock Selection
Bit Clock Select
MCLKSEL
[7]
MCLKSEL
[6]
MCLKSEL
[5]
Mode
BCLKSEL
[4]
BCLKSEL
[3]
BCLKSEL
[2]
Mode
0
0
0
1
0
0
0
1
(BCLK=MCLK)
0
0
1
1.5
0
0
1
2
(BCLK=MCLK/2)
0
1
0
2
0
1
0
4
0
1
1
3
0
1
1
8
1
0
0
4
1
0
0
16
1
0
1
6
1
0
1
32
1
1
0
8
1
1
0
Reserved
1
1
1
12
1
1
1
Reserved
Name
Source of Internal Clock master
clock source selection control
Enables chip master mode to
drive FS and BCLK outputs
Bit
CLKM[8]
CLKIOEN[0]
0
MCLK (PLL Bypassed)
MCLK pin used as master clock
Slave Mode
(FS and BCLK are inputs)
1
MCLK (PLL Output)
Internal PLL oscillator output
used as master clock
Master Mode
(FS and BCLK are driven as
outputs by internally generated
clocks)
NAU8812
emPowerAudio
™
Datasheet Revision 2.0 Page 68 of 109 January 2011
13.3.4. Audio Sample Rate Control Register
Addr
D8
D7
D6
D5
D4
D3
D2
D1
D0
Default
0x07
0
0
0
0
0
SMPLR[2:0]
SCLKEN
0x000
The Audio sample rate configures the coefficients for the internal digital filters
Sample Rate Selection
SMPLR[3]
SMPLR[2]
SMPLR[1]
Mode (Hz)
0
0
0
48 k
0
0
1
32 k
0
1
0
24 k
0
1
1
16 k
1
0
0
12 k
1
0
1
8 k
1
1
0
Reserved
1
1
1
Reserved
NAU8812 provides a slow clock to be used for both the jack insert detect debounce circuit and the zero cross
timeout.
Bit
Slow Clock Enable
SCLKEN[0]
0
MCLK
1
PLL Output (Period 221 * MCLK)
NAU8812
emPowerAudio
™
Datasheet Revision 2.0 Page 69 of 109 January 2011
13.3.5. GPIO Control Register
Addr
D8
D7
D6
D5
D4
D3
D2
D1
D0
Default
0x08
0
0
0
GPIOPLL[4:5]
GPIOPL
GPIOSEL[2:0]
0x000
General Purpose I/O Selection
GPIOSEL
[2]
GPIOSEL
[1]
GPIOSEL
[0]
Mode (Hz)
0
0
0
CSb Input
0
0
1
Jack Insert Detect
0
1
0
Temperature OK
0
1
1
AMUTE Active
1
0
0
PLL CLK Output
1
0
1
PLL Lock
1
1
0
1
1
1
1
0
PLL Output Clock Divider
GPIO Polarity
GPIOPLL[5]
GPIOPLL[4]
Mode
Bit
GPIOPL[3]
0
0
1
0
Normal
0
1
2
1
Inverted
1
0
3
1
1
4
13.3.6. DAC Control Register
Addr
D8
D7
D6
D5
D4
D3
D2
D1
D0
Default
0x0A
0
0
DACMT
DEEMP[1:0]
DACOS
AUTOMT
0
DACPL
0x000
Name
Soft Mute Enable
Over Sample Rate
Auto Mute enable
Polarity Invert
Bit
DACMT[6]
DACOS[3]
AUTOMT[2]
DACPL[0]
0
Disable
64x
(Lowest power)
Disable
Normal
1
Enable
128x
(best SNR)
Enable
DAC Output
Inverted
NAU8812
emPowerAudio
™
Datasheet Revision 2.0 Page 70 of 109 January 2011
De-emphasis
DEEMP[5]
DEEMP[4]
Mode
0
0
No de-emphasis
0
1
32kHz sample rate
1
0
44.1kHz sample rate
1
1
48kHz sample rate
13.3.7. DAC Gain Control Register
Addr
D8
D7
D6
D5
D4
D3
D2
D1
D0
Default
0x0B
0
DACGAIN
0x0FF
DAC Gain
DACGAIN[7:0]
Mode (dB)
B7
B6
B5
B4
B3
B2
B1
B0
0
0
0
0
0
0
0
0
Digital
Mute
0
0
0
0
0
0
0
1
-127.0
0
0
0
0
0
0
1
0
-126.5
0
0
0
0
0
0
1
1
-126.0
DAC Gain Range -127dB to 0dB @ 0.5 increments
1
1
1
1
1
1
0
0
-1.5
1
1
1
1
1
1
0
1
-1.0
1
1
1
1
1
1
1
0
-0.5
1
1
1
1
1
1
1
1
0.0
13.3.8. ADC Control Register
Addr
D8
D7
D6
D5
D4
D3
D2
D1
D0
Default
0x0E
HPFEN
HPFAM
HPF[2:0]
ADCOS
0
0
ADCPL
0x100
Name
High Pass Filter
Enable
Audio or Application
Mode
Over Sample
Rate
ADC Polarity
Bit
HPFEN[8]
HPFAM[7]
ADCOS[3]
ADCPL[0]
0
Disable
Audio (1st order, fc ~ 3.7 kHz)
64x (Lowest power)
Normal
1
Enable
Application (2nd order, fc = HPF)
128x (best SNR)
Inverted
NAU8812
emPowerAudio
™
Datasheet Revision 2.0 Page 71 of 109 January 2011
High Pass Filter
fs ( kHz)
HPF[6]
HPF[5]
HPF[4]
SMPLR=101
SMPLR=100
SMPLR=011
SMPLR=010
SMPLR=001
SMPLR=000
B2
B1
B0
8
11.025
12
16
22.05
24
32
44.1
48
0
0
0
82
113
122
82
113
122
82
113
122
0
0
1
102
141
153
102
141
153
102
141
153
0
1
0
131
180
156
131
180
156
131
180
156
0
1
1
163
225
245
163
225
245
163
225
245
1
0
0
204
281
306
204
281
306
204
281
306
1
0
1
261
360
392
261
360
392
261
360
392
1
1
0
327
450
490
327
450
490
327
450
490
1
1
1
408
563
612
408
563
612
408
563
612
13.3.9. ADC Gain Control Register
Addr
D8
D7
D6
D5
D4
D3
D2
D1
D0
Default
0x0F
0
ADCGAIN
0x0FF
ADC Gain
ADCGAIN[7:0]
Mode (dB)
B7
B6
B5
B4
B3
B2
B1
B0
0
0
0
0
0
0
0
0
Unused
0
0
0
0
0
0
0
1
-127.0
0
0
0
0
0
0
1
0
-126.5
0
0
0
0
0
0
1
1
-126.0
ADC Gain Range -127dB to 0dB @ 0.5 increments
1
1
1
1
1
1
0
0
-1.5
1
1
1
1
1
1
0
1
-1.0
1
1
1
1
1
1
1
0
-0.5
1
1
1
1
1
1
1
1
0.0
NAU8812
emPowerAudio
™
Datasheet Revision 2.0 Page 72 of 109 January 2011
13.4. DIGITAL TO ANALOG CONVERTER (DAC) LIMITER REGISTERS
Addr
D8
D7
D6
D5
D4
D3
D2
D1
D0
Default
0x18
DACLIMEN
DACLIMDCY[3:0]
DACLIMATK[3:0]
0x032
0x19
0
0
DACLIMTHL[2:0]
DACLIMBST[3:0]
0x000
DAC Limiter Decay time (per 6dB gain change) for 44.1
kHz sampling. Note that these will scale with sample
rate
DAC Limiter Attack time (per 6dB gain change) for 44.1
kHz sampling. Note that these will scale with sample rate
DACLIMDCY[3:0]
DACLIMATK[3:0]
B3
B2
B1
B0
Decay Time
B3
B2
B1
B0
Attack Time
0
0
0
0
544.0 us
0
0
0
0
68 us
0
0
0
1
1.1 ms
0
0
0
1
136 us
0
0
1
0
2.2 ms
0
0
1
0
272 us
0
0
1
1
4.4 ms
0
0
1
1
544 us
0
1
0
0
8.7 ms
0
1
0
0
1.1 ms
0
1
0
1
17.4 ms
0
1
0
1
2.2 ms
0
1
1
0
35.0 ms
0
1
1
0
4.4 ms
0
1
1
1
69.6 ms
0
1
1
1
8.7 ms
1
0
0
0
139.0 ms
1
0
0
0
17.4 ms
1
0
0
1
278.5 ms
1
0
0
1
35 ms
1
0
1
0
557.0 ms
1
0
1
0
69.6 ms
1
0
1
1
1.1 s
1
0
1
1
139 ms
To
To
1
1
1
1
1
1
1
1
NAU8812
emPowerAudio
™
Datasheet Revision 2.0 Page 73 of 109 January 2011
DAC Limiter Programmable signal threshold level
(determines level at which the limiter starts to operate)
DAC Limiter volume Boost (can be used as a
stand alone volume Boost when
DACLIMEN=0)
DACLIMTHL[3:0]
Threshold
(dB)
DACLIMBST[3:0]
Boost
(dB)
B2
B1
B0
B3
B2
B1
B0
0
0
0
-1
0
0
0
0
0
0
0
1
-2
0
0
0
1
+1
0
1
0
-3
0
0
1
0
+2
0
1
1
-4
0
0
1
1
+3
1
0
0
-5
0
1
0
0
+4
1
0
1
-6
0
1
0
1
+5
To
0
1
1
0
+6
1
1
1
0
1
1
1
+7
1
0
0
0
+8
1
0
0
1
+9
DAC Digital Limiter
1
0
1
0
+10
Bit
DACLIMEN[8]
1
0
1
1
+11
0
Disabled
1
1
0
0
+12
1
Enabled
1
1
0
1
Reserved
To
1
1
1
1
13.5. NOTCH FILTER REGISTERS
Addr
D8
D7
D6
D5
D4
D3
D2
D1
D0
Default
0x1B
NFCU
NFCEN
NFCA0[13:7]
0x000
0x1C
NFCU
0
NFCA0[6:0]
0x000
0x1D
NFCU
0
NFCA1[13:7]
0x000
0x1E
NFCU
0
NFCA1[6:0]
0x000
The Notch Filter is enabled by setting NFCEN[7] address (0x1B) bit to HIGH. The coefficients, A0 and A1, should be
converted to 2‟s complement numbers to determine the register values. A0 and A1 are represented by the register
bits NFCA0[13:0] and NFCA1[13:0]. Since there are four register of coefficients, a Notch Filter Update bit is provided
so that the coefficients can be updated simultaneously. NFCU[8] is provided in all registers of the Notch Filter
coefficients but only one bit needs to be toggled for LOW - HIGH - LOW for an update. If any of the NFCU[8] bits are
left HIGH then the Notch Filter coefficients will continuously update. An example of how to calculate is provided in
the Notch Filter section.
NAU8812
emPowerAudio
™
Datasheet Revision 2.0 Page 74 of 109 January 2011
Name
A0
A1
Notation
Register Value (DEC)
Coefficient
s
b
s
b
ff
ff
2
2
tan1
2
2
tan1
s
c
ff
xA
2
cos1 0
fc = center frequency (Hz)
fb = -3dB bandwidth (Hz)
fs = sample frequency (Hz)
NFCA0 = -A0 x 213
NFCA1 = -A1 x 212
(then convert to 2‟s
complement)
13.6. AUTOMATIC LEVEL CONTROL REGISTER
13.6.1. ALC1 REGISTER
Addr
D8
D7
D6
D5
D4
D3
D2
D1
D0
Default
0x20
ALCEN
0
0
ALCMXGAIN[2:0]
ALCMNGAIN[2:0]
0x038
Maximum Gain
Minimum Gain
ALCMXGAIN[2:0]
Mode
ALCMNGAIN[2:0]
Mode
B2
B1
B0
B2
B1
B0
0
0
0
-6.75dB
0
0
0
-12dB
0
0
1
-0.75dB
0
0
1
-6dB
0
1
0
+5.25dB
0
1
0
0dB
0
1
1
+11.25dB
0
1
1
+6dB
1
0
0
+17.25dB
1
0
0
+12dB
1
0
1
+23.25dB
1
0
1
+18dB
1
1
0
+29.25dB
1
1
0
+24dB
1
1
1
+35.25dB
1
1
1
+30dB
Name
ALC Enable
Bit
ALCEN[8]
0
Disabled (PGA gain set by PGAGAIN
register bits)
1
Enabled (ALC controls PGA gain)
NAU8812
emPowerAudio
™
Datasheet Revision 2.0 Page 75 of 109 January 2011
13.6.2. ALC2 REGISTER
Addr
D8
D7
D6
D5
D4
D3
D2
D1
D0
Default
0x21
ALCZC
ALCHT[3:0]
ALCSL[3:0]
0x00B
ALC HOLD TIME before gain is increased.
ALC TARGET – sets signal level at ADC input
ALCHT[3:0]
ALC Hold
Time (sec)
ALCSL[3:0]
ALC Target
Level (dB)
B7
B6
B5
B4
B3
B2
B1
B0
0
0
0
0
0
0
0
0
0
-28.5 fs
0
0
0
1
2 ms
0
0
0
1
-27 fs
0
0
1
0
4 ms
0
0
1
0
25.5 fs
Time Doubles with every increment
ALC Target Level Range
-28.5dB to -6dB @ 1.5dB increments
1
0
0
0
256 ms
1
0
1
1
-12 fs
1
0
0
1
512 ms
1
1
0
0
-10.5 fs
1
0
1
0
1 s
1
1
0
1
-9 fs
To
1
1
1
0
-7.5 fs
1
1
1
1
1
1
1
1
-6 fs
Name
ALC Zero Crossing
Detect
Bit
ALCZC[8]
0
Disabled
1
Enabled
It is recommended that zero crossing should not be used in conjunction with the ALC or Limiter functions
NAU8812
emPowerAudio
™
Datasheet Revision 2.0 Page 76 of 109 January 2011
13.6.3. ALC3 REGISTER
Addr
D8
D7
D6
D5
D4
D3
D2
D1
D0
Default
0x22
ALCM
ALCDCY[3:0]
ALCATK[3:0]
0x032
ALC DECAY TIME
ALCDCY[3:0]
ALCM = 0 (Normal Mode)
ALCM = 1 (Limiter Mode)
B3
B2
B1
B0
Per Step
Per 6dB
90% of
Range
Per Step
Per 6dB
90% of
Range
0
0
0
0
500 us
4 ms
28.78 ms
125 us
1 ms
7.2 ms
0
0
0
1
1 ms
8 ms
57.56 ms
250 us
2 ms
14.4 ms
0
0
1
0
2 ms
16 ms
115 ms
500 us
4 ms
28.8 ms
Time doubles with every increment
1
0
0
0
128 ms
1 s
7.37 s
32 ms
256 ms
1.8 s
1
0
0
1
256 ms
2 s
14.7 s
64 ms
512 ms
3.7 s
1
0
1
0
512 ms
4 s
29.5 s
128 ms
1 s
7.37 s
To
1
1
1
1
ALC ATTACK TIME
ALCATK[3:0]
ALCM = 0 (Normal Mode)
ALCM = 1 (Limiter Mode)
B3
B2
B1
B0
Per Step
Per 6dB
90% of
Range
Per Step
Per 6dB
90% of
Range
0
0
0
0
125 us
1 ms
7.2 ms
31 us
248 us
1.8 ms
0
0
0
1
250 us
2 ms
14.4 ms
62 us
496 us
3.6 ms
0
0
1
0
500 us
4 ms
28.85 ms
124 us
992 us
7.15 ms
Time doubles with every increment
1
0
0
0
26.5 ms
256 ms
1.53 s
7.9 ms
63.2 ms
455.8 ms
1
0
0
1
53 ms
512 ms
3.06 s
15.87 ms
127 ms
916 ms
1
0
1
0
128 ms
1 s
7.89 s
31.7ms
254 ms
1.83 s
To
1
1
1
1
NAU8812
emPowerAudio
™
Datasheet Revision 2.0 Page 77 of 109 January 2011
13.7. NOISE GAIN CONTROL REGISTER
Addr
D8
D7
D6
D5
D4
D3
D2
D1
D0
Default
0x23
0
0
0
0
0
ALCNEN
ALCNTH[2:0]
0x000
Noise Gate Enable
Noise Gate Threshold
Bit
ALCNEN[3]
ALCNTH[2:0]
Mode
0
Disabled
B2
B1
B0
1
Enabled
0
0
0
-39 dB
0
0
1
-45 dB
0
1
0
-51 dB
0
1
1
-57 dB
1
0
0
-63 dB
1
0
1
-69 dB
1
1
0
-75 dB
1
1
1
-81 dB
NAU8812
emPowerAudio
™
Datasheet Revision 2.0 Page 78 of 109 January 2011
13.8. PHASE LOCK LOOP (PLL) REGISTERS
13.8.1. PLL Control Registers
Addr
D8
D7
D6
D5
D4
D3
D2
D1
D0
Default
0x24
0
0
0
0
PLLMCLK
PLLN[3:0]
0x008
PLL Integer
PLL Clock
PLLN[3:0]
Frequency
Ratio
Bit
PLLMCLK[4]
B3
B2
B1
B0
0
MCLK not divided
0
0
0
1
Not Valid
1
Divide MCLK by 2 before input
PLL
To
0
1
0
0
0
1
0
1
5
0
1
1
0
6
0
1
1
1
7
1
0
0
0
8
1
0
0
1
9
1
0
1
0
10
1
0
1
1
11
1
1
0
0
12
1
1
0
1
13
1
1
1
0
Not Valid
1
1
1
1
13.8.2. Phase Lock Loop Control (PLL) Registers
Addr
D8
D7
D6
D5
D4
D3
D2
D1
D0
Default
0x25
0
0
0
PLLK[23:18]
0x00C
0x26
PLLK[17:9]
0x093
0x27
PLLK[8:0]
0x0E9
Fractional (K) part of PLLK1 – PLLK3 input/output frequency ratio
NAU8812
emPowerAudio
™
Datasheet Revision 2.0 Page 79 of 109 January 2011
13.9. INPUT, OUTPUT, AND MIXERS CONTROL REGISTER
13.9.1. Attenuation Control Register
Addr
D8
D7
D6
D5
D4
D3
D2
D1
D0
Default
0x28
0
0
0
0
0
0
MOUTATT
SPKATT
0
0x000
Attenuation Control
Name
Attenuation control for bypass path (output of
input boost stage) to speaker mixer and MONO
mixer input
Bit
MOUTATT[2]
SPKATT[1]
0
0 dB
0 dB
1
-10 dB
-10 dB
13.9.2. Input Signal Control Register
Addr
D8
D7
D6
D5
D4
D3
D2
D1
D0
Default
0x2C
MICBIASV
0
0
0
AUXM
AUXPGA
NMICPGA
PMICPGA
0x003
Auxiliary Input mode
AUX amplifier output to
input PGA signal source
MICN to input PGA
negative terminal
Input PGA amplifier
positive terminal to
MIC+ or VREF
Bit
AUXM[3]
AUXPGA[2]
NMICPGA[1]
PMICPGA[0]
0
Inverting Buffer
AUX not connected to
input PGA
MICN not connected to
input PGA
Input PGA Positive
terminal to VREF
1
Mixer (Internal Resistor
bypassed)
AUX to input PGA
Negative terminal
MICN to input PGA
Negative terminal.
Input PGA Positive
terminal to MICP
through variable resistor
Microphone Bias Voltage Control
MICBIASV[8:7]
Address (0x2C)
MICBIASM[4] = 0
Address (0x28)
MICBIASM[4] = 1
Address (0x28)
0
0
0.9* VDDA
0.85* VDDA
0
1
0.65* VDDA
0.60* VDDA
1
0
0.75* VDDA
0.70* VDDA
1
1
0.50* VDDA
0.50* VDDA
NAU8812
emPowerAudio
™
Datasheet Revision 2.0 Page 80 of 109 January 2011
13.9.3. PGA Gain Control Register
Addr
D8
D7
D6
D5
D4
D3
D2
D1
D0
Default
0x2D
0
PGAZC
PGAMT
PGAGAIN[5:0]
0x010
Programmable Gain Amplifier Gain
PGAGAIN[5:0]
B5
B4
B3
B2
B1
B0
Gain
0
0
0
0
0
0
-12.00 dB
0
0
0
0
0
1
-11.25 dB
0
0
0
0
1
0
-10.50 dB
:::
:::
:::
:::
:::
:::
:::
0
0
1
1
1
1
-0.75 dB
0
1
0
0
0
0
0 dB
0
1
0
0
0
1
+0.75 dB
PGA Gain Range -12dB to +35.25dB @ 0.75
increment
:::
:::
:::
:::
:::
:::
:::
1
1
1
1
0
1
33.75
1
1
1
1
1
0
34.50
1
1
1
1
1
1
35.25
PGA Zero Cross Enable
Mute Control for PGA
Bit
PGAZC[7]
PGAMT[6]
0
Update gain when gain
register changes
Normal Mode
1
Update gain on 1st zero
cross after gain register
write
PGA Muted
NAU8812
emPowerAudio
™
Datasheet Revision 2.0 Page 81 of 109 January 2011
13.9.4. ADC Boost Control Registers
Addr
D8
D7
D6
D5
D4
D3
D2
D1
D0
Default
0x2F
PGABST
0
PMICBSTGAIN
0
AUXBSTGAIN
0x100
MIC+ pin to the input Boost Stage
(NB, when using this path set
PMICPGA=0):
Auxiliary to Input Boost Stage
PMICBSTGAIN[2:0]
Gain (dB)
AUXBSTGAIN[2:0]
Gain (dB)
B2
B1
B0
B2
B1
B0
0
0
0
Path
Disconnected
0
0
0
Path
Disconnected
0
0
1
-12
0
0
1
-12
0
1
0
-9
0
1
0
-9
0
1
1
-6
0
1
1
-6
1
0
0
-3
1
0
0
-3
1
0
1
0
1
0
1
0
1
1
0
+3
1
1
0
+3
1
1
1
+6
1
1
1
+6
Name
Input Boost
Bit
PGABST[8]
0
PGA output has +0dB gain through input Boost stage
1
PGA output has +20dB gain through input Boost stage
13.9.5. Output Register
Addr
D8
D7
D6
D5
D4
D3
D2
D1
D0
Default
0x31
0
0
0
0
0
MOUTBST
SPKBST
TSEN
AOUTIMP
0x002
MONO Output Boost Stage
Speaker Output Boost
Stage
Thermal Shutdown
Analog Output Resistance
Bit
MOUTBST[3]
SPKBST[2]
TSEN[1]
AOUTIMP[0]
0
(1.0 x VREF) Gain Boost
(1.0 x VREF) Gain Boost
Disabled
~1kΩ
1
(1.5 x VREF) Gain Boost
(1.5 x VREF) Gain Boost
Enabled
~30 kΩ
NAU8812
emPowerAudio
™
Datasheet Revision 2.0 Page 82 of 109 January 2011
13.9.6. Speaker Mixer Control Register
Addr
D8
D7
D6
D5
D4
D3
D2
D1
D0
Default
0x32
0
0
0
AUXSPK
0
0
0
BYPSPK
DACSPK
0x001
Auxiliary to Speaker Mixer
Bypass path (output of
Boost stage) to Speaker
Mixer
DAC to Speaker Mixer
Bit
AUXSPK[5]
BYPSPK[1]
DACSPK[0]
0
Disconnected
Disconnected
Disconnected
1
Connected
Connected
Connected
13.9.7. Speaker Gain Control Register
Addr
D8
D7
D6
D5
D4
D3
D2
D1
D0
Default
0x36
0
SPKZC
SPKMT
SPKGAIN[5:0]
0x039
Speaker Gain
SPKGAIN[5:0]
B5
B4
B3
B2
B1
B0
Gain (dB)
0
0
0
0
0
0
-57.0
0
0
0
0
0
1
-56.0
0
0
0
0
1
0
-55.0
:::
:::
:::
:::
:::
:::
:::
1
1
1
0
0
0
-1.0
1
1
1
0
0
1
0.0
1
1
1
0
1
0
+1.0
Speaker Gain Range -57 dB to +6 dB @ +1
increment
:::
:::
:::
:::
:::
:::
:::
1
1
1
1
0
1
+4.0
1
1
1
1
1
0
+5.0
1
1
1
1
1
1
+6.0
Speaker Gain Control Zero Cross
Speaker Output
Bit
SPKZC[7]
SPKMT[6]
0
Change Gain on Zero Cross
ONLY
Speaker Enabled
1
Change Gain Immediately
Speaker Muted
NAU8812
emPowerAudio
™
Datasheet Revision 2.0 Page 83 of 109 January 2011
13.9.8. MONO Mixer Control Register
Addr
D8
D7
D6
D5
D4
D3
D2
D1
D0
Default
0x38
0
0
MOUTMXMT
0
0
0
AUXMOUT
BYPMOUT
DACMOUT
0x001
MOUT Mute
Auxiliary to
MONO Mixer
Bypass path (output of Boost
Stage) to MONO Mixer
DAC to
MONO Mixer
Bit
MOUTMXMT[6]
AUXMOUT[2]
BYPMOUT[1]
DACMOUT[0]
0
Not Muted
Disconnected
Disconnected
Disconnected
1
Muted
Connected
Connected
Connected
During mute, the MONO output will output VREF that can be used as a DC reference for a headphone out.
13.9.9. Trimming Register
Addr
D8
D7
D6
D5
D4
D3
D2
D1
D0
Default
0x3A
LPIPBST
LPADC
LPSPKD
LPDAC
MICBIASM
TRIMREG[3:2]
IBADJ[1:0]
0x000
B1
B0
Trim Output Regulator (V)
Adjust Master Bias of the Analog Portion
TRIMREG[3:2]
IBADJ[1:0]
0
0
1.800
Default Current Consumption
0
1
1.610
25% Current Increase from Default
1
0
1.400
14% Current Decrease from Default
1
1
1.218
25% Current Decrease from Default
Trim regulator bits can be used only when VDDD <2.7V.
Low Power IP
Boost
Low Power ADC
Low Power
Speaker Driver
Low Power DAC
Microphone bias
Mode selection
Bit
LPIPBST[8]
LPADC[7]
LPSPKD[6]
LPDAC[5]
MICBIASM[4]
0
Normal Function
Normal Function
Normal Function
Normal Function
Disable
1
Cut power in half
Cut power in half
Cut power in half
Cut power in half
Enable
Note cutting the power in half will directly affect the audio performances.
NAU8812
emPowerAudio
™
Datasheet Revision 2.0 Page 84 of 109 January 2011
13.10. PCM TIME SLOT CONTROL & ADCOUT IMPEDANCE OPTION CONTROL
13.10.1. PCM1 TIMESLOT CONTROL REGISTER
Addr
D8
D7
D6
D5
D4
D3
D2
D1
D0
Default
0x3B
TSLOT[8:0]
0x000
Transmit and receive timeslot are expressed in number of BCLK cycles in a 10-bit word. The most significant bit
TSLOT[9] is located in register PCMTS2[0] address (0x3C). Timeslot, TSLOT[9:0], determines the start point for the
timeslot on the PCM interface for data in the transmit direction.
13.10.2. PCM2 TIMESLOT CONTROL REGISTER
Addr
D8
D7
D6
D5
D4
D3
D2
D1
D0
Default
0x3C
PCMTSEN
TRI
PCM8BIT
PUDOEN
PUDPE
PUDPS
LOUTR
PCMB
TSLOT[9]
0x000
Name
PCM Transit
Enable
Tri-state PCMT
LSB
PCM Word Length
Left and Right
Channel have
same data
PCM Mode2
Bit
PCMTSEN[8]
TRI[7]
PCM8BIT[6]
LOUTR
PCMB
0
PCM A
Drive the full Clock
of LSB
Use WLEN[6:5] to
select Word Length
Disable
Disable
1
PCM Time Slot
Tri-State the 2nd
half of LSB
Audio interface will
be 8 Bit Word
Length
Enable
Enable
If TRI = 1 and PUDOEN = 0, the device will drive the LSB bit 1st half of BCLK out of the ADCOUT pin (stop driving
after LSB BCLK Rising edge) but if TRI = 0 or PUDOEN = 1 this feature is disabled, full BCLK of LSB will be driven
the LSB value.
Figure 41: The Programmable ADCOUT Pin
PUDOE
ADCOUT
iADCOUT
PUDPE
PUDPS
NAU8812
emPowerAudio
™
Datasheet Revision 2.0 Page 85 of 109 January 2011
Internal ADC
out data
Power Up and Down
Output Enable
Power Up and
Down Pull Enable
Power Up and Down
Pull Select
OUTPUT
iADCOUT
PUDOEN[5]
PUDPE[4]
PUDPS[3]
PAD
0
1
x
x
0
1
1
x
x
1
x
0
0
x
Hi-Z
x
0
1
0
Pull-Low
x
0
1
1
Pull-High
13.11. REGISTER ID (READ ONLY)
13.11.1. Device revision register
Addr
D8
D7
D6
D5
D4
D3
D2
D1
D0
Default
0x3E
0
1
1
1
0
1
1
1
1
0x0EF
READ ONLY
Device revision ID
13.11.2. 2-WIRE ID Register (READ ONLY)
Addr
D8
D7
D6
D5
D4
D3
D2
D1
D0
Default
0x3F
0
0
0
0
1
1
0
1
0
0x01A
READ ONLY
First 7 bits (D0 – D6) of the 2-Wire device ID excluding the LSB read/write bit.
13.11.3. Additional ID (READ ONLY)
Addr
D8
D7
D6
D5
D4
D3
D2
D1
D0
Default
0x40
0
1
1
0
0
1
0
1
0
0x0CA
READ ONLY
NAU8812
emPowerAudio
™
Datasheet Revision 2.0 Page 86 of 109 January 2011
13.12. Reserved
Addr
D8
D7
D6
D5
D4
D3
D2
D1
D0
Default
0x41
1
0
0
1
0
0
1
0
0
0x124
13.13. OUTPUT Driver Control Register
Addr
D8
D7
D6
D5
D4
D3
D2
D1
D0
Default
0x45
0
MOUTMT
0
HVOPU
0
HVOP
0x001
Bit
Location
Bit Description
Bit Name
Bit Value
0
1
0
Override to automatic
3V/5V bias selection
HVOP
set internal output biasing to be
optimal for 3.6Vdc or lower
operation
Note: For this to be effective
HVOPU[2] address 0x45 must
set
set internal output biasing to be
optimal for higher than 3.6Vdc
operation
Note: For this to be effective
HVOPU[2] address 0x45 must set
2
Update bit for HV
override feature
HVOPU
High Voltage override Disable
This bit must set in conjunction with
HVOP[0] address 0x45 for the
automatic override to be effective
4
Headphone output mute
MOUTMT
Disable
Enable
During mute, the MONO output will output VREF that can be used as a DC reference for a headphone out.
NAU8812
emPowerAudio
™
Datasheet Revision 2.0 Page 87 of 109 January 2011
13.14. AUTOMATIC LEVEL CONTROL ENHANCED REGISTER
13.14.1. ALC1 Enhanced Register
Addr
D8
D7
D6
D5
D4
D3
D2
D1
D0
Default
0x46
0
ALCPKSEL
ALCNGSEL
ALCGAINL[5:0] (READ ONLY)
0x001
Bit
Location
Bit Description
Bit Name
Bit Value
0
1
5:0
Display PGA and ALC Gain
ALCGAINL
ALC Disabled: Display PGA Gain
ALC Enabled: Display Real Time ALC Gain
6
Choose peak or peak-to-peak value
for Noise Gate threshold logic
ALCNGSEL
use peak-to-peak
detector output value
use rectified peak
detector output value
7
Choose peak or peak-to-peak value
for ALC threshold logic
ALCPKSEL
use rectified peak
detector output value
use peak-to-peak
detector output value
13.14.2. ALC Enhanced 2 Register
Addr
D8
D7
D6
D5
D4
D3
D2
D1
D0
Default
0x47
PKLIMEN
0
0x000
Bit
Location
Bit Description
Bit Name
Bit Value
0
1
8
Enable control for ALC fast
peak limiter function
PKLIMEN
Enable
Disable
NAU8812
emPowerAudio
™
Datasheet Revision 2.0 Page 88 of 109 January 2011
13.15. MISC CONTROL REGISTER
Addr
D8
D7
D6
D5
D4
D3
D2
D1
D0
Default
0x49
SPIEN
FSERRVAL[1:0]
FSERFLSH
FSERRENA
NFDLY
DACINMT
PLLLOCKP
DACOS256
0x000
Bit
Location
Bit Description
Bit Name
Bit Value
0
1
0
Set DAC to use 256x
oversampling rate
DACOS256
Use oversampling rate as
determined by Register 0x0A[3]
(default)
Set DAC to 256x
oversampling rate regardless
of Register 0x0A[3]
1
Enable control to use PLL
output when PLL is not in
phase locked condition
PLLLOCKP
PLL VCO output disabled when
PLL is in unlocked condition
(default)
PLL VCO output used as-is
when PLL is in unlocked
condition
2
Enable control to mute
DAC limiter output when
softmute is enabled
DACINMT
DAC limiter output may not
move to exactly zero during
Softmute (default)
DAC limiter output muted to
exactly zero during Softmute
3
Enable control to delay use
of notch filter output when
filter is enabled
NFDLY
Delay using notch filter output
512 sample times after notch
enabled (default)
Use notch filter output
immediately after notch filter
is enabled
4
Enable control for short
frame cycle detection logic
FSERRENA
Short frame cycle detection
logic enabled
Short frame cycle detection
logic disabled
5
Enable DSP state flush on
short frame sync event
FSERFLSH
Ignore short frame sync events
(default)
Set DSP state to initial
conditions on short frame
sync event
8
Set SPI control bus mode
regardless of state of Mode
pin
SPIEN
Default Operation
Force SPI 4-wire mode
regardless of state of Mode
pin
B1
B0
Short frame sync detection period value
trigger if frame time less than
FSERRVAL[1:0]
0
0
255 MCLK edges
0
1
253 MCLK edges
1
0
254 MCLK edges
1
1
255 MCLK edges
MODE
Pin
SPIEN[8]
Bit
Address
Description
0
0
0x49
2-Wire Interface (Write/Read)
1
0
SPI Interface 16-bit (Write ONLY)
x
1
SPI Interface 32-bit (Read)
SPI Interface 24-bit (Write)
(SSOP 28-Pin Write ONLY,
QFN 32-Pin Write/Read)
NAU8812
emPowerAudio
™
Datasheet Revision 2.0 Page 89 of 109 January 2011
13.16. Output Tie-Off REGISTER
Addr
D8
D7
D6
D5
D4
D3
D2
D1
D0
Default
0x4B
0
LPSPKA
MANVREFH
MANVREFM
MANVREFL
0x000
Bit
Location
Bit Description
Bit Name
Bit Value
0
1
0
Direct manual control for switch for
VREF 6k-ohm resistor to ground
MANVREFL
switch to ground controlled
by Register 0x01 setting
switch to ground in the
closed position
1
Direct manual control for switch for
VREF 160k-ohm resistor to ground
MANVREFM
switch to ground controlled
by Register 0x01 setting
switch to ground in the
closed position
2
Direct manual control of switch for
VREF 600k-ohm resistor to ground
MANVREFH
switch to ground controlled
by Register 0x01 setting
switch to ground in the
closed position
7
Amplifier Stage
LPSPKA
Two-stage amplifier for
speaker driver
Three-stage amplifier
for speaker driver
13.17. ALC PEAK-TO-PEAK READOUT REGISTER
Addr
D8
D7
D6
D5
D4
D3
D2
D1
D0
Default
0x4C
P2PDET
0x000
Bit Location
Bit Description
Bit Name
0 - 8
READ ONLY Register
Outputs the instantaneous value contained in the peak-to-peak amplitude register used
by the ALC for signal level dependent logic. Value is highest of left or right input when
both inputs are under ALC control.
P2PDET
13.18. ALC PEAK READOUT REGISTER
Addr
D8
D7
D6
D5
D4
D3
D2
D1
D0
Default
0x4D
PDET
0x000
Bit Location
Bit Description
Bit Name
0 - 8
READ ONLY Register
Outputs the instantaneous value contained in the peak detector amplitude register
used by the ALC for signal level dependent logic. Value is highest of left or right input
when both inputs are under ALC control.
PDET
NAU8812
emPowerAudio
™
Datasheet Revision 2.0 Page 90 of 109 January 2011
13.19. AUTOMUTE CONTROL AND STATUS READ REGISTER
Addr
D8
D7
D6
D5
D4
D3
D2
D1
D0
Default
0x4E
0
0
AMTCTRL
HVDET
NSGATE
AMUTE
DMUTE
0
FTDEC
0x000
Bit
Location
Bit Description
Bit Name
Bit Value
0
1
0
Peak limiter indicator
FASTDEC
Below 87.5% of full scale
Above 87.5% of full scale
2
READ ONLY BIT
Digital Mute function of the DAC
DMUTE
Digital gain greater than zero
Digital gain is zero either by
.- Direct setting
.- Softmute function
3
READ ONLY BIT
Analog Mute function applied to DAC
AMUTE
Automute Disabled
Automute Enabled
4
READ ONLY BIT
Logic controlling the Noise Gate
NSGATE
Signal is greater than the noise
gate threshold and ALC gain
can change
Signal is less than the noise
gate threshold and ALC gain is
held constant
5
READ ONLY BIT
High voltage detection circuit monitoring
VDDSPK voltage
HVDET
VDDSPK logic switch voltage
threshold measured as 4.0Vdc
or Less
VDDSPK logic switch voltage
threshold measured as 4.0Vdc
or Greater
6
Select observation point used by DAC
output Automute feature
AMTCTRL
Automute operates on data at
the input to the DAC digital
attenuator (default)
Automute operates on data at
the DACIN input pin
13.20. Output Tie-off Direct Manual Control REGISTER
Addr
D8
D7
D6
D5
D4
D3
D2
D1
D0
Default
0x4F
MANOUTEN
SBUFH
SBUFL
SNSPK
SPSPK
SMOUT
0
0
0
0x000
Bit
Location
Bit Description
Bit Name
Bit Value
0
1
3
If MANUOUTEN = 1, use this bit to
control Auxout1 output tie-off
resistor switch
SMOUT
Tie-off resistor switch for MOUT
output is forced open
Tie-off resistor switch for
MOUT output is forced
closed
4
If MANUOUTEN = 1, use this bit to
control left speaker output Tie-off
resistor switch
SPSPK
Tie-off resistor switch for
SPKOUTP speaker output is
forced open
Tie-off resistor switch for
SPKOUTP speaker output
is forced closed
5
If MANUOUTEN = 1, use this bit to
control left speaker output Tie-off
resistor switch
SNSPK
Tie-off resistor switch for
SPKOUTN speaker output is
forced open
Tie-off resistor switch for
SPKOUTN speaker output
is forced closed
6
If MANUOUTEN = 1, use this bit to
control bypass switch around 1.0x
non-boosted output Tie-off buffer
amplifier
SBUFL
Normal automatic operation of
bypass switch
Bypass switch in closed
position when output buffer
amplifier is disabled
7
If MANUOUTEN = 1, use this bit to
control bypass switch around 1.5x
boosted output Tie-off buffer
amplifier
SBUFH
Normal automatic operation of
bypass switch
Bypass switch in closed
position when output buffer
amplifier is disabled
8
Enable direct control over output
Tie-off resistor switching
MANOUTEN
Ignore Register 0x4F bits to
control input Tie-off
resistor/buffer switching
Use Register 0x4F bits to
override automatic Tie-off
resistor/buffer switching
NAU8812
emPowerAudio
™
Datasheet Revision 2.0 Page 91 of 109 January 2011
14. CONTROL INTERFACE TIMING DIAGRAM
14.1. SPI WRITE TIMING DIAGRAM
Figure 42: SPI Write Timing Diagram
14.2. SPI READ TIMING DIAGRAM
Figure 43: SPI Read Timing Diagram
TRISE
TFALL
CSB
SCLK
SDIO
TSCK
TSCKH
TSCKL
TSCCSH
TSDIOS
TSDIOH
TCSBH
TCSBL
TRISE
TFALL
CSB
SCLK
SDIO
GPIO1
TSCK
TSCKH
TSCKL
TCSSCS TSCCSH
TSDIOS
TSDIOH
TG3D
TCSBH
TG3ZD
TZG3D
NAU8812
emPowerAudio
™
Datasheet Revision 2.0 Page 92 of 109 January 2011
SYMBOL
DESCRIPTION
MIN
TYP
MAX
UNIT
TSCK
SCLK Cycle Time
80
---
---
ns
TSCKH
SCLK High Pulse Width
35
---
---
ns
TSCKL
SCLK Low Pulse Width
35
---
---
ns
TRISE
Rise Time for all SPI Signals
---
---
10
ns
TFALL
Fall Time for all SPI Signals
---
---
10
ns
TCSSCS
CSb Falling Edge to 1st SCLK Falling Edge Setup Time (4
wire SPI only)
30
---
---
ns
TSCCSH
Last SCLK Rising Edge to CSb Rising Edge Hold Time
30
---
---
ns
TCSBL
CSb Low Time
30
---
---
ns
TCSBH
CSb High Time between CSb Lows
30
---
---
ns
TSDIOS
SDIO to SCLK Rising Edge Setup Time
20
---
---
ns
TSDIOH
SCLK Rising Edge to SDIO Hold Time
20
---
---
ns
TZG3D
Delay Time from CSb Falling Edge to SO Active
(4 wire SPI Only)
--
--
15
ns
TG3ZD
Delay Time from CSb Rising Edge to SO Tri-state (4 wire
SPI Only)
--
--
15
ns
TG3D
Delay Time from SCLK Falling Edge to SO (4 wire SPI Only)
---
---
15
ns
Table 34: SPI Timing Parameters
NAU8812
emPowerAudio
™
Datasheet Revision 2.0 Page 93 of 109 January 2011
14.3. 2-WIRE TIMING DIAGRAM
Figure 44: 2-Wire Timing Diagram
SYMBOL
DESCRIPTION
MIN
TYP
MAX
UNIT
TSTAH
START / Repeat START condition, SCLK falling edge to
SDIO falling edge hold timing
600
---
---
ns
TSTAS
Repeat START condition, SDIO rising edge to SCLK
falling edge setup timing
600
---
---
ns
TSTOS
STOP condition, SDIO rising edge to SCLK rising edge
setup timing
600
---
---
ns
TSCKH
SCLK High Pulse Width
600
---
---
ns
TSCKL
SCLK Low Pulse Width
1.3
---
---
us
TRISE
Rise Time for all 2-Wire Signals
---
---
300
ns
TFALL
Fall Time for all 2-Wire Signals
---
---
300
ns
TSDIOS
SDIO to SCLK Rising Edge DATA Setup Time
100
---
---
ns
TSDIOH
SCLK falling Edge to SDIO DATA Hold Time
0
---
600
ns
Table 35: 2-WireTiming Parameters
TSTAH TSTAH
TSTOS
TSTAS
TSDIOS TSDIOH
TSCKL
TSCKH
TRISE
TFALL
SCLK
SDIO
NAU8812
emPowerAudio
™
Datasheet Revision 2.0 Page 94 of 109 January 2011
15. AUDIO INTERFACE TIMING DIAGRAM
15.1. AUDIO INTERFACE IN SLAVE MODE
TFSH
TFSS
TFSH TFSS
TDIS
TDIH
TDOD
TBCK
TBCKH TBCKL
TRISE
TFALL
BCLK
(Slave)
FS
(Slave)
DACIN
ADCOUT
Figure 45: Audio Interface Slave Mode Timing Diagram
15.2. AUDIO INTERFACE IN MASTER MODE
TFSD TFSD
TDIS
TDIH
TDOD
BCLK
(Master)
FS
(Master)
DACIN
ADCOUT
Figure 46: Audio Interface in Master Mode Timing Diagram
NAU8812
emPowerAudio
™
Datasheet Revision 2.0 Page 95 of 109 January 2011
15.3. PCM AUDIO INTERFACE IN SLAVE MODE (PCM Audo Data)
Figure 47: PCM Audio Interface Slave Mode Timing Diagram
15.4. PCM AUDIO INTERFACE IN MASTER MODE (PCM Audo Data)
Figure 48: PCM Audio Interface Slave Mode Timing Diagram
TFSH
TFSS
TFSH TFSS
TDIS
TDIH
TDOD
TBCK
TBCKH
TBCKL
TRISE
TFALL
BCLK
(Slave)
FS
(Slave)
DACIN
ADCOUT MSB
MSB
TFSD TFSD
TDIS
TDIH
TDOD
BCLK
(Master)
FS
(Master)
DACIN
ADCOUT
MSB
MSB
TFSD
NAU8812
emPowerAudio
™
Datasheet Revision 2.0 Page 96 of 109 January 2011
15.5. PCM AUDIO INTERFACE IN SLAVE MODE (PCM Time Slot Mode )
Figure 49: PCM Audio Interface Slave Mode (PCM Time Slot Mode )Timing Diagram
15.6. PCM AUDIO INTERFACE IN MASTER MODE (PCM Time Slot Mode )
Figure 50: PCM Audio Interface Master Mode (PCM Time Slot Mode )Timing Diagram
TFSH
TFSS
TFSH TFSS
TDIS
TDIH
TDOD
TBCK
TBCKH
TBCKL
TRISE
TFALL
BCLK
(Slave)
FS
(Slave)
DACIN
ADCOUT
TDOD1
MSB
MSB
TFSD TFSD
TDIS
TDIH
TDOD
BCLK
(Master)
FS
(Master)
DACIN
ADCOUT
MSB
MSB
NAU8812
emPowerAudio
™
Datasheet Revision 2.0 Page 97 of 109 January 2011
SYMBOL
DESCRIPTION
MIN
TYP
MAX
UNIT
TBCK
BSCK Cycle Time (Slave Mode)
50
---
---
ns
TBCKH
BSCK High Pulse Width (Slave Mode)
20
---
---
ns
TBCKL
BSCK Low Pulse Width (Slave Mode)
20
---
---
ns
TFSS
fs to SCK Rising Edge Setup Time (Slave Mode)
20
---
---
ns
TFSH
SCK Rising Edge to fs Hold Time (Slave Mode)
20
---
---
ns
TFSD
fs to SCK falling to fs transition (Master Mode)
---
---
10
ns
TRISE
Rise Time for All Audio Interface Signals
---
---
10
ns
TFALL
Fall Time for All Audio Interface Signals
---
---
10
ns
TDIS
ADCIN to SCK Rising Edge Setup Time
15
---
---
ns
TDIH
SCK Rising Edge to ADCIN Hold Time
15
---
---
ns
TDOD
Delay Time from SCLK falling Edge to DACOUT
---
---
10
ns
Table 36: Audio Interface Timing Parameters
15.7. System Clock (MCLK) Timing Diagram
Figure 51: MCLK Timing Diagram
PARAMETER
SYMBOL
TEST CONDITIONS
MIN
TYP
MAX
UNIT
MCLK Duty Cycle
TMCLKDC
60:40
40:60
MCLK High Pulse Width
TMCLKH
20
---
---
ns
MCLK Low Pulse Width
TMCLKL
20
---
---
ns
Table 37: MCLK Timing Parameter
TMCLKL
MCLK
TMCLKH
NAU8812
emPowerAudio
™
Datasheet Revision 2.0 Page 98 of 109 January 2011
15.8. µ-LAW ENCODE DECODE CHARACTERISTICS
Normalized
Encode
Decision
Levels
Digital Code
Normalized
Decode
Levels
D7
D6
D5
D4
D3
D2
D1
D0
Sign
Chord
Chord
Chord
Step
Step
Step
Step
8159
1
0
0
0
0
0
0
0
8031
7903
:
:
:
:
:
:
:
:
:
:
4319
1
0
0
0
1
1
1
1
4191
4063
:
:
:
:
:
:
:
:
:
:
2143
1
0
0
1
1
1
1
1
2079
2015
:
:
:
:
:
:
:
:
:
:
1055
1
0
1
0
1
1
1
1
1023
991
:
:
:
:
:
:
:
:
:
:
511
1
0
1
1
1
1
1
1
495
479
:
:
:
:
:
:
:
:
:
:
239
1
1
0
0
1
1
1
1
231
223
:
:
:
:
:
:
:
:
:
:
103
1
1
0
1
1
1
1
1
99
95
:
:
:
:
:
:
:
:
:
:
35
1
1
1
0
1
1
1
1
33
31
:
:
:
:
:
:
:
:
:
:
3
1
1
1
1
1
1
1
0
2
1
:
:
:
:
:
:
:
:
:
1
1
1
1
1
1
1
1
0
0
Notes:
Sign bit = 0 for negative values, sign bit = 1 for positive values
NAU8812
emPowerAudio
™
Datasheet Revision 2.0 Page 99 of 109 January 2011
15.9. A-LAW ENCODE DECODE CHARACTERISTICS
Normalized
Encode
Decision
Levels
Digital Code
Normalized
Decode
Levels
D7
D6
D5
D4
D3
D2
D1
D0
Sign
Chord
Chord
Chord
Step
Step
Step
Step
4096
1
0
1
0
1
0
1
0
4032
3968
:
:
:
:
:
:
:
:
:
:
2176
1
0
1
0
0
1
0
1
2112
2048
:
:
:
:
:
:
:
:
:
:
1088
1
0
1
1
0
1
0
1
1056
1024
:
:
:
:
:
:
:
:
:
:
544
1
0
0
0
0
1
0
1
528
512
:
:
:
:
:
:
:
:
:
:
272
1
0
0
1
0
1
0
1
264
256
:
:
:
:
:
:
:
:
:
:
136
1
1
1
0
0
1
0
1
132
128
:
:
:
:
:
:
:
:
:
:
68
1
1
1
0
0
1
0
1
66
64
:
:
:
:
:
:
:
:
:
:
2
1
1
0
1
0
1
0
1
1
0
Notes:
1. Sign bit = 0 for negative values, sign bit = 1 for positive values
2. Digital code includes inversion of all even number bits
NAU8812
emPowerAudio
™
Datasheet Revision 2.0 Page 100 of 109 January 2011
15.10. µ-LAW / A-LAW CODES FOR ZERO AND FULL SCALE
Level
µ-Law
A-Law
Sign bit
(D7)
Chord bits
(D6,D5,D4)
Step bits
(D3,D2,D1,D0)
Sign bit
(D7)
Chord bits
(D6,D5,D4)
Step bits
(D3,D2,D1,D0)
+ Full Scale
1
000
0000
1
010
1010
+ Zero
1
111
1111
1
101
0101
- Zero
0
111
1111
0
101
0101
- Full Scale
0
000
0000
0
010
1010
15.11. µ-LAW / A-LAW OUTPUT CODES (DIGITAL MW)
Sample
µ-Law
A-Law
Sign bit
(D7)
Chord bits
(D6,D5,D4)
Step bits
(D3,D2,D1,D0)
Sign bit
(D7)
Chord bits
(D6,D5,D4)
Step bits
(D3,D2,D1,D0)
1
0
001
1110
0
011
0100
2
0
000
1011
0
010
0001
3
0
000
1011
0
010
0001
4
0
001
1110
0
011
0100
5
1
001
1110
1
011
0100
6
1
000
1011
1
010
0001
7
1
000
1011
1
010
0001
8
1
001
1110
1
011
0100
NAU8812
emPowerAudio
™
Datasheet Revision 2.0 Page 101 of 109 January 2011
16. DIGITAL FILTER CHARACTERISTICS
PARAMETER
TEST
CONDITIONS
MIN
TYP
MAX
UNIT
ADC Filter
Passband
+/- 0.025dB
0
0.454*fs
-6dB
0.5*fs
Passband Ripple
+/-0.025
dB
Stopband
0.546*fs
Stopband
Attenuation
f > 0.546*fs
-60
dB
Group Delay
21/fs
ADC High Pass Filter
High Pass Filter
Corner Frequency
-3dB
3.7
Hz
-0.5dB
10.4
-0.1dB
21.6
DAC Filter
Passband
+/- 0.035dB
0
0.454*fs
-6dB
0.5*fs
Passband Ripple
+/-0.035
dB
Stopband
0.546*fs
Stopband
Attenuation
f > 0.546*fs
-55
dB
Group Delay
29/fs
Table 57 Digital Filter Characteristics
TERMINOLOGY
1. Stop Band Attenuation (dB) – the degree to which the frequency spectrum is attenuated (outside audio band)
2. Pass-band Ripple – any variation of the frequency response in the pass-band region
3. Note that this delay applies only to the filters and does not include
NAU8812
emPowerAudio
™
Datasheet Revision 2.0 Page 102 of 109 January 2011
Figure 52: DAC Filter Frequency Response
Figure 53: ADC Filter Frequency Response
Figure 54: DAC Filter Ripple
Figure 55: ADC Filter Ripple
NAU8812
emPowerAudio
™
Datasheet Revision 2.0 Page 103 of 109 January 2011
17. TYPICAL APPLICATION
Figure 56: Application Diagram 28-Pin SSOP
C8
1uF
C7
1uF
R2
1.2k ohm R1
1.2k ohm
CSb/GPIO
AUX
VDDSPK
VDDSPK
SPKOUT -
VSSSPK
VSSSPK
SPKOUT +
MOUT
MODE
SDIO
SCLK
VREF
MIC -
MIC +
MICBIAS
NC
VDDA
VSSA
VSSA
VDDC
VDDB
VSSD
ADCOUT
DACIN
FS BCLK
MCLK
2
3
4
5
6
7
8
1
10
11
12
13
14
9
27
26
25
24
23
22
21
28
19
18
17
16
15
20
NAU8812
MONO AUDIO
CODEC
SSOP 28-Pin
C3
4.7uF
C2
4.7uF
C1
4.7uF
C9
4.7uF
VSS
C5
1uF
VSS
C4
4.7uF
VSS
C10
1uF
VDDA
VDDC
VDDB
VDDSPK
C6
4.7uF
NAU8812
emPowerAudio
™
Datasheet Revision 2.0 Page 104 of 109 January 2011
Figure 57: Application Diagram for 32-Pin QFN
Note 1: All non-polar capacitors are assumed to be low ESR type parts, such as with MLC construction or similar. If
capacitors are not low ESR, additional 0.1uF and/or 0.01uF capacitors may be necessary in parallel with the
bulk 4.7uF capacitors on the supply rails.
Note 2: Load resistors to ground on outputs may be helpful in some applications to insure a DC path for the output
capacitors to charge/discharge to the desired levels. If the output load is always present and the output load
provides a suitable DC path to ground, then the additional load resistors may not be necessary. If needed,
such load resistors are typically a high value, but a value dependent upon the application requirements.
Note 3: To minimize pops and clicks, large polarized output capacitors should be a low leakage type.
Note 4: Depending on the microphone device and PGA gain settings, common mode rejection can be improved by
choosing the resistors on each node of the microphone such that the impedance presented to any noise on
either microphone wire is equal.
NAU8812
MONO AUDIO
CODEC
QFN 32-Pin
SPKOUT -
BCLK
MCLK
2
3
4
5
6
7
8
1
10
11
12
13
14
15
16
9
31
30
29
28
27
26
25
32
23
22
21
20
19
18
17
NC
VSSA
VDDL
SPKOUT +
MOUT
SDIO
NC
SO
MIC -
MIC +
AUX
SCLK
ADCOUT
DACIN
FS
MODE
VDDA
VSSA
VDDC
VDDB
VSSD
VSSSPK
VSSSPK
VSSD
CSb/GPIO
24
VDDSPK
VDDSPK
VREF
C5
1uF
VDDA
C3
4.7uF
C2
4.7uF
C1
4.7uF
C11
10nF
VDDSPK C4
4.7uF
C10
1uF
C9
4.7uF
VSS
MICBIAS
C8
1uF
C7
1uF
R2
1.2k ohm R1
1.2k ohm
C6
4.7uF
VDDC
VDDB
VSS
NAU8812
emPowerAudio
™
Datasheet Revision 2.0 Page 105 of 109 January 2011
18. PACKAGE SPECIFICATION
18.1. 28 Pin SSOP
0
0.002
0.197
0.291
7.80
0
7.40
8
8.20
5.30
b
E
D
c
10.05
5.00
A1
A2
A
5.60
10.35
10.20
2.00
1.85
8
0.323
0.307
0.073
0.079
0.220
0.395
0.407
0.401
0.209
MIN.
DIMENSION IN INCH
SYMBOL
DIMENSION IN MM
MIN.
NOM
MAX.
MAX.
NOM
0.05
e
L
L1
Y
0.009
0.015
0.004
0.010
0.021
0.030
0.050
0.004
0.22
0.38
0.09
0.25
0.65
0.0256
0.55
0.75
1.25
0.10
H
E
0.95
0.037
1.75
1.65
0.065
0.069
1
28
D
E
e
Y
b
A1
A2
A
SEATING PLANE
DTEAIL A
L
L1
DETAIL A
SEATING PLANE
E
H
14
15
b
NAU8812
emPowerAudio
™
Datasheet Revision 2.0 Page 106 of 109 January 2011
32-Pin QFN
NAU8812
emPowerAudio
™
Datasheet Revision 2.0 Page 107 of 109 January 2011
19. ORDERING INFORMATION
Nuvoton Part Number Description
NAU8812_ _
Package Type:
R = 28-Pin SSOP Package
Y = 32-Pin QFN Package
Package Material:
G = Pb-free Package
NAU8812
emPowerAudio
™
Datasheet Revision 2.0 Page 108 of 109 January 2011
20. VERSION HISTORY
VERSION
DATE
PAGE
DESCRIPTION
1.0
September 2009
Preliminary release
1.1
November 2009
13 - 15
36
38
69
108
Updated Figure numbers
The word SPKBST was updated with VDDSPK
Figure 19 updated
Figure 20 updated
Description of CLKM and CLKIOEN is updated
Updated type on the VERSION
1.2
December 2009
3
13 - 15
66
67
Note Added
Electrical Specification table format updated
Register 0x05 description updated
Register 0x06 description updated
1.3
January 2010
46 - 48
Control interface description updated
1.4
January 2010
107
Package description updated
1.5
February 2010
22
Figure 7 updated
1.6
March 2010
14
63, 87
63, 87
Speaker THD for 2-stage updated
Bit-8 of register 0x46 deleted from the document.
Default value of register 0x47 updated
1.7
April 2010
4
44
62
63, 86
Block diagram updated
Table 24 updated
Table 34 updated
Register 0x41 Reserved updated
2.0
January 2011
47
63
79
97
Removed trailing clock cycle from SPI timing diagram
Corrected Register 0x38 Register name
Improved description of Mic Bias set up
Added System Clock Timing Diagram
Important Notice
Nuvoton products are not designed, intended, authorized or warranted for use as components in systems or
equipment intended for surgical implantation, atomic energy control instruments, airplane or spaceship
instruments, transportation instruments, traffic signal instruments, combustion control instruments, or for
other applications intended to support or sustain life. Furthermore, Nuvoton products are not intended for
applications wherein failure of Nuvoton products could result or lead to a situation where in personal injury,
death or severe property or environmental damage could occur.
NAU8812
emPowerAudio
™
Datasheet Revision 2.0 Page 109 of 109 January 2011
Nuvoton customers using or selling these products for use in such applications do so at their own risk and
agree to fully indemnify Nuvoton for any damages resulting from such improper use or sales.
