AS3400 AS3410 AS3430
Low Power Ambient Noise-Cancelling Speaker Driver
www.austriamicrosystems.com Revision 1.02 1 - 51
1 General Description
The AS3400/10/30 are speaker driver with Ambient Noise Cancelling
function for handsets, headphones or ear pieces. It is intended to
improve quality of e.g. music listening, a phone conversation etc. by
reducing background ambient noise.
The fully analog implementation allows the lowest power
consumption, lowest system BOM cost and most natural received
voice enhancement otherwise difficult to achieve with DSP
implementations. The device is designed to be easily applied to
existing architectures.
An internal OTP-ROM can be optionally used to store the
microphones gain calibration settings.
The AS3400/10/30 can be used in different configurations for best
trade-off of noise cancellation, required filtering functions and
mechanical designs.
The simpler feed-forward topology is used to effectively reduce low
frequency background noise. The feed-back topology with either 1 or
2 filtering stages can be used to reduce noise for a larger frequency
range, and to even implement transfer functions like speaker
equalization, Baxandall equalization, high/low shelving filter and to
set a predefined loop bandwidth.
The filter loop is optimized by the user for specific handset electrical
and mechanical designs by dimensioning simple R, C components.
Most handset implementations will make use of a single noise
detecting microphone. Two microphones could be used to allow for
increased flexibility of their location in the handset mechanical
design. Using the bridged mode allows to even drive high impedance
headsets.
2 Key Features
Microphone Input
128 gain steps @ 0.375dB and MUTE with AGC
Differential, low noise microphone amplifier
Single ended or differential mode
Improved supply for electret microphone
MIC gain OTP programmable
High Efficiency Headphone Amplifier
2x34mW, 0.1% THD @ 16Ω, 1.5V supply,
100dB SNR
Bridged mode for e.g. 300Ω loads
Click and pop less start-up and mode switching
Line Input
Volume control via serial interface or volume pin
64 steps @ 0.75dB and MUTE, pop-free gain setting
Single ended stereo or mono differential mode
ANC processing
Feed-forward cancellation
Feed-back cancellation with filter loop transfer function
definable via simple RC components
Simple in production SW calibration
12-30dB noise reduction (headset dependent)
10-2000Hz wide frequency active noise attenuation (headset
dependent)
Monitor Function
For assisted hearing, i.e. to monitor announcements
Fixed (OTP prog.) ambient sound amplification to compensate
headphone passive attenuation
Volume controlled ambient sound amplification mixed with fixed
(OTP prog.) attenuation of LineIn
Incremental Fu nctions
ANC with or without music on the receiving path
Improved dynamic range playback
OTP ROM for automatic trimming during production (4 times
programbable)
Performance Parameter
5/3.8mA @ 1.5V stereo/mono ANC; <1µA quiescent
Extended PSRR for 217Hz
Interfaces
2-wire serial control mode & volume inputs
Calibration via Line-In or 2-wire serial interface (patent pending)
Single cell or fixed 1.0-1.8V supply with internal CP
Package
AS3400, AS3410 QFN24 [4x4mm] 0.5mm pitch
AS3430 QFN32 [5.x5mm] 0.5mm pitch
3 Applications
The devices are ideal for Ear pieces, Headsets, Hands-Free Kits,
Mobile Phones, and Voice Communicating Devices.
www.austriamicrosystems.com Revision 1.02 2 - 51
AS3400 AS3410 AS3 430 1v0
Data Sheet - Applications
Figure 1. AS3410 Feed Forward ANC Block Diagram
Figure 2. AS3430 Feed-Back Block Diagram
www.austriamicrosystems.com Revision 1.02 3 - 51
AS3400 AS3410 AS3 430 1v0
Data Sheet - Applications
Figure 3. AS3400 Feed-Back Block Diagram
Figure 4. AS3400 Feed Forward Block Diagram
www.austriamicrosystems.com Revision 1.02 4 - 51
AS3400 AS3410 AS3 430 1v0
Data Sheet - Contents
Contents
1 General Description .................................................................................................................................................................. 1
2 Key Features............................................................................................................................................................................. 1
3 Applications............................................................................................................................................................................... 1
4 Pin Assignments ....................................................................................................................................................................... 4
4.1 Pin Descriptions.................................................................................................................................................................................... 5
5 Absolute Maximum Ratings ...................................................................................................................................................... 7
6 Electrical Characteristics........................................................................................................................................................... 8
7 Typical Operating Characteristics ............................................................................................................................................. 9
8 Detailed Description................................................................................................................................................................ 12
8.1 Audio Line Input.................................................................................................................................................................................. 12
8.1.1 Gain Stage................................................................................................................................................................................. 12
8.1.2 Parameter .................................................................................................................................................................................. 12
8.2 Microphone Input................................................................................................................................................................................ 13
8.2.1 Gain Stage & Limiter.................................................................................................................................................................. 13
8.2.2 Supply........................................................................................................................................................................................ 13
8.2.3 Parameter .................................................................................................................................................................................. 14
8.3 Headphone Output ............................................................................................................................................................................. 15
8.3.1 Input Multiplexer ........................................................................................................................................................................ 15
8.3.2 No-Pop Function........................................................................................................................................................................ 15
8.3.3 No-Clip Function ........................................................................................................................................................................ 15
8.3.4 Over-Current Protection............................................................................................................................................................. 15
8.3.5 Parameter .................................................................................................................................................................................. 16
8.4 Operational Amplifier .......................................................................................................................................................................... 16
8.4.1 Parameter .................................................................................................................................................................................. 16
8.5 SYSTEM............................................................................................................................................................................................. 17
8.5.1 Power Up/Down Conditions....................................................................................................................................................... 17
8.5.2 Start-up Sequence..................................................................................................................................................................... 17
8.5.3 Mode Switching ......................................................................................................................................................................... 18
8.5.4 Status Indication ........................................................................................................................................................................ 19
8.6 VNEG Charge Pump .......................................................................................................................................................................... 19
8.6.1 Parameter .................................................................................................................................................................................. 19
8.7 OTP Memory & Internal Registers...................................................................................................................................................... 19
8.7.1 Register & OTP Memory Configuration ..................................................................................................................................... 19
8.7.2 OTP Fuse Burning..................................................................................................................................................................... 20
8.8 2-Wire-Serial Control Interface ........................................................................................................................................................... 21
8.8.1 Protocol...................................................................................................................................................................................... 21
8.8.2 Parameter .................................................................................................................................................................................. 24
9 Register Description................................................................................................................................................................ 25
10 Application Information ......................................................................................................................................................... 38
11 Package Drawings and Markings.......................................................................................................................................... 43
12 Ordering Information............................................................................................................................................................. 47
www.austriamicrosystems.com Revision 1.02 5 - 51
AS3400 AS3410 AS3 430 1v0
Data Sheet - Pin Assignments
4 Pin Assignments
Note: Pin assignment may change in preliminary data sheets.
Figure 5. Pin Assignments (Top Vie w)
AS3400
QFN 24pin
AGND 1
LINL 2
LINR 3
VOL_CSDA 4
MODE_CSCL 5
MICL 6
HPVDD
18
HPR
17
HPL
16
VSS
15
QOP2R
14
IOP2R
13
MICS 7
MICR 8
QMICR 9
QLINR 10
IOP1R 11
QOP1R 12
24 QMICL
23 VNEG
22 CPN
21 GND
20 CPP
19 VBAT
VNEG or open25
AS3410
QFN 24pin
AGND
1
LINL
2
LINR
3
VOL_CSDA
4
MODE_CSCL
5
6
HPVDD
18
HPR
17
HPL
16
VSS
15
QOP1R
14
13
MICS
7
MICR
8
QMICR
9
IOP1R
10
11
12
24
QOP1L
23
VNEG
22
CPN
21
GND
20
CPP
19
QMICL
MICL
ILED
VBAT
IOP1L
VNEG or open25
AS3430
QFN 32pin
IOP1L 1
QLINL 2
QMICL 3
AGND 4
LINL 5
LINR 6
VOL_CSDA 7
VBAT
24
HPVDD
23
HPR
22
HPVSS
21
HPL
20
VSS
19
QOP2R
18
MICL 9
ILED 10
MICS 11
MICR 12
QMICR 13
QLINR 14
IOP1R 15
QOP1R 16 n.c.
32 QOP1L
31 IOP2L
30 QOP2L
29 VNEG
28 CPN
27 GND
26 CPP
25
MODE_CSCL 8IOP2R17
Exposed Pad: VNEG
or open
33
www.austriamicrosystems.com Revision 1.02 6 - 51
AS3400 AS3410 AS3 430 1v0
Data Sheet - Pin Assignments
4.1 Pin Descriptions
Note: Pin description may change in preliminary data sheets.
Table 1. Pin Description for AS3400 AS3410 AS3430
Pin Name Pin Number Type Description
AS3400 AS3410 AS3430
IOP1L - 24 1 ANA IN Filter OpAmp1 Input Left Channel
QLINL - - 2 ANA OUT Line In GainStage Output Left Channel
QMICL 24 1 3 ANA OUT MIC GainStage Output Right Channel
AGND 1 2 4 ANA IN Analog Reference
LINL 235 ANA IN
DIG IN
Line In Left Channel
During Appl Trim Mode Write – CSDA
During Appl Trim Mode Burn – VNEG
LINR 346 ANA IN
DIG IO
LineIn Right Channel
During Appl Trim Mode Write – CSCL
During Appl Trim Mode Burn – Clock
VOL_CSDA 4 5 7 MIXED IO Serial Interface Data
ADC Input for volume regulation
MODE_CSCL 5 6 8 DIG IN Mode Pin (PowerUp/Dn, Monitor)
Serial Interface Clock
MICL 6 7 9 ANA IN Microphone In Left Channel
ILED - 8 10 ANA OUT Current Output for on-indication LED
MICS 7 9 11 ANA OUT Microphone Supply
MICR 8 10 12 ANA IN Microphone Input Right Channel
QMICR 9 11 13 ANA OUT MIC GainStage Output Right Channel
QLINR 10 - 14 ANA OUT Line In GainStage Output Right Channel
IOP1R 11 12 15 ANA IN FilterOpAmp1 Input Right Channel
QOP1R 121316 ANA IN
Filter OpAmp1 Output Right Channel
IOP2R 13 - 17 ANA IN Filter OpAmp2 Input Right Channel
QOP2R 14 - 18 ANA OUT Filter OpAmp2 Output Right Channel
VSS 15 14 19 SUP IN Core and Periphery Circuit VSS Supply
HPL 161520 ANA OUT
Headphone Output Left Channel
HPVSS - - 21 SUP IN Headphone VSS Supply
HPR 171622 ANA OUT
Headphone Output Right Channel
HPVDD 181723 SUP IN
Headphone VDD Supply
VBAT 191824 SUP IN
VNEG ChargePump Positive Supply
n.c. - - 25 -
CPP 201926 ANA OUT
VNEG ChargePump Flying Capacitor Positive Terminal
GND 212027 GND
VNEG ChargePump Negative Supply
CPN 222128 ANA OUT
VNEG ChargePump Flying Capacitor Negative Terminal
VNEG 23 22 29 SUP IO VNEG ChargePump Output
www.austriamicrosystems.com Revision 1.02 7 - 51
AS3400 AS3410 AS3 430 1v0
Data Sheet - Pin Assignments
QOP2L - - 30 ANA OUT Filter OpAmp2 Output Left Channel
IOP2L - - 31 ANA IN Filter OpAmp2 Input Left Channel
QOP1L - 23 32 ANA OUT Filter OpAmp1 Output Right Channel
25 25 33 Exposed Pad: connect to VNEG or leave it unconnected
Table 1. Pin Description for AS3400 AS3410 AS3430
Pin Name Pin Number Type Description
AS3400 AS3410 AS3430
www.austriamicrosystems.com Revision 1.02 8 - 51
AS3400 AS3410 AS3 430 1v0
Data Sheet - Absolute Maximum Ratings
5 Absolute Maximum Ratings
Stresses beyond those listed in Table 2 may cause permanent damage to the device. These are stress ratings only, and functional operation of
the device at these or any other conditions beyond those indicated in Electrical Characteristics on page 9 is not implied. Exposure to absolute
maximum rating conditions for extended periods may affect device reliability. The device should be operated under recommended operating
conditions.
Table 2. Absolute Maximum Ratings
Parameter Min Max Units Comments
Reference Ground Defined as in GND
Supply terminals -0.5 2.0 V Applicable for pin VBAT, HPVDD
Ground terminals -0.5 0.5 V Applicable for pins AGND
Negative terminals -2.0 0.5 V Applicable for pins VNEG, VSS, HPVSS
Voltage difference at VSS terminals -0.5 0.5 V Applicable for pins VSS, HPVSS
Pins with protection to VBAT VNEG
-0.5
5.0
VBAT+0.5 V Applicable for pins CPP, CPN
Pins with protection to HPVDD VSS
-0.5
5.0
HPVDD+0.5 VApplicable for pins LINL/R, MICL/R, ILED, HPR,
HPL, QMICL/R, QLINL/R, IOPx, QOPx
other pins VSS
-0.5 5Applicable for pins MICS, VOL_CSDA,
MODE_CSCL
Input Current (latch-up immunity) -100 100 mA Norm: JEDEC 17
Continuous Power Dissipation (TA = +70ºC)
Continuous Power Dissipation -200mW
PT1 for QFN16/24/32 package
1. Depending on actual PCB layout and PCB used
Electrostatic Discharge
Electrostatic Discharge HBM +/-2 kV Norm: JEDEC JESD22-A114C
Temperature Ranges and Storage Conditions
Junction Temperature +110 ºC
Storage Temperature Range -55 +125 ºC
Humidity non-condensing 585%
Moisture Sensitive Level 3 Represents a max. floor life time of 168h
Package Body Temperature 260 ºC
The reflow peak soldering temperature (body
temperature) specified is in accordance with IPC/
JEDEC J-STD-020“Moisture/Reflow Sensitivity
Classification for Non-Hermetic Solid State
Surface Mount Devices”.
www.austriamicrosystems.com Revision 1.02 9 - 51
AS3400 AS3410 AS3 430 1v0
Data Sheet - Electrical Characteristics
6 Electrical Characteristics
VBAT = 1.0V to 1.8V, TA = -20ºC to +85ºC. Typical values are at VBAT = 1.5V, TA = +25ºC, unless otherwise specified.
Table 3. Electrical Characteristics
Symbol Parameter Condition Min Max Unit
TAAmbient Temperature Range -20 +85 °C
Supply Voltages
GND Reference Ground 00V
VBAT,
HPVDD Battery Supply Voltage normal operation with MODE pin high 1.0 1.8 V
Two wire interface operation 1.4 1.8 V
VNEG ChargePump Voltage -1.8 -0.7 V
VSS Analog neg. Supply Voltages
HPVSS, VSS, VNEG -1.8 -0.7 V
VDELTA-Difference of Ground Supplies
GND, AGND
To achieve good performance, the negative
supply terminals should be connected to low
impedance ground plane.
-0.1 0.1 V
VDELTA-- Difference of Negative Supplies
VSS, VNEG, HPVSS Charge pump output or external supply -0.1 0.1 V
VDELTA+Difference of Positive Supplies VBAT-HPVDD -0.25 0.25 V
Other pins
VMICS Microphone Supply Voltage MICS 0 3.6 V
VHPVDD Pins with diode to HPVDD MICL/R, ILED, HPR, HPL, QMICL/R, QLINL/
R, IOPx, QOPx VSS 3.6 V
VVBAT Pins with diode to VBAT CPP, CPN VNEG VBAT V
VCONTROL Control Pins MODE_CSCL, VOL_CSDA VSS 3.7 V
VTRIM Line Input & Application Trim Pins LINL, LINR VNEG -0.5
or -1.8
HPVDD +0.5
or 1.8 V
Symbol Parameter Condition Min Typ Max Unit
Ileak Leakage current VBAT<0.8V 20 µA
VBAT<0.6V 10 µA
Block Power Requirements @ 1.5V VBAT
ISYS Reference supply current Bias generation, oscillator, ILED current sink,
ADC6 0.25 mA
ILIN LineIn gain stage current no signal, stereo 0.64 mA
IMIC Mic gain stage current no signal, stereo 2.10 mA
IHP Headphone stage current no signal 1.70 mA
IVNEG VNEG charge pump current no load 0.25 mA
IMICS MICS charge pump current no load 0.06 mA
IMIN Minimal supply current Sum of all above blocks 5.00 mA
IOP1 OP1 supply current no load 0.64 mA
IOP2 OP2 supply current no load 0.64 mA
IILED ILED current sink current 100% duty cycle 2.50 mA
IMICB Microphone bias current 200µA per microphone via charge pump 1.30 mA
www.austriamicrosystems.com Revision 1.02 10 - 51
AS3400 AS3410 AS3 430 1v0
Data Sheet - Typical Operating Characteristics
7 Typical Operating Characteristics
VBAT = +1.5V, TA = +25ºC, unless otherwise specified.
Figure 6. LIN to HPH: THD+N vs. Output Power
Figure 7. VNEG Charge Pump
THD+N vs POUT - 32Ω - stereo single ended
0,01
0,1
1
0 5 10 15 20 25 30 35 40
Pout [mW]
THD+N [%]
VBAT=1.8V
VBAT=1.5V
VBAT=1.0V
THD+N vs POUT - 16Ω - single ended stereo
0,01
0,1
1
0102030405060
Pout [mW]
THD+N [%]
VBAT=1.8V
VBAT=1.5V
VBAT=1.0V
THD+N vs POUT - 32Ω - bridged-tied load
0,01
0,1
1
0 102030405060708090100110120130
Pout [mW]
THD+N [%]
VBAT=1.8V
VBAT=1.5V
VBAT=1.0V
THD+N vs POUT - 64Ω - bridged-tied load
0,01
0,1
1
0 102030405060708090
Pout [mW]
THD+N [%]
VBAT=1.8V
VBAT=1.5V
VABT=1.0V
VNEG CP Voltage vs Load Current
-1,8
-1,6
-1,4
-1,2
-1,0
-0,8
-0,6
-0,4
-0,2
0,0
0 50 100 150 200
I_VNEG [mA]
V_VNEG [V]
VBAT=1.0V
VBAT=1.5V
VBAT=1.8V
VNEG CP Efficiency
50
55
60
65
70
75
80
85
90
95
100
0 20 40 60 80 100 120 140 160 180 200
I_VNEG [mA]
Eff [%]
VBAT=1.0V
VBAT=1.5V
VBAT=1.8V
www.austriamicrosystems.com Revision 1.02 11 - 51
AS3400 AS3410 AS3 430 1v0
Data Sheet - Typical Operating Characteristics
Figure 8. Microphone Supply Generation
Figure 9. ILED Current Sink (100% PWM setting)
MICS Charge Pump
0
0,5
1
1,5
2
2,5
3
3,5
0 500 1000 1500 2000
I_MICS [uA]
V_MICS [V]
VBAT=1.8V
VBAT=1.5V
VABT=1.0V
I_MICS vs dI_VBAT
0
1000
2000
3000
4000
5000
6000
7000
0 500 1000 1500 2000
I_MICS [uA]
dI_VBAT [uA]
VBAT=1.8V
VBAT=1.5V
VBAT=1.0V
V_MICS vs V_VBAT
1,5
1,7
1,9
2,1
2,3
2,5
2,7
2,9
3,1
3,3
3,5
0,9 1,0 1,1 1,2 1,3 1,4 1,5 1,6 1,7 1,8
VBAT [V]
V_MICS [V]
I_MCS = 0. 0uA
I_MICS = 600uA
R_MICS_Switch vs V_VBAT
40
50
60
70
80
90
100
110
120
130
140
0,9 1,0 1,1 1,2 1,3 1,4 1,5 1,6 1,7 1,8
VBAT [V]
R_MICS_Switch [Ω]
ILED Current
0,0
20,0
40,0
60,0
80,0
100,0
120,0
0,00,10,20,30,40,5
V (ILED-VNEG) [V]
I (ILED) [%
]
ILED (Vbat= 1.8V )
ILED (Vbat= 1.5V )
ILED (Vbat= 1.0V )
ILED Current
0,0
20,0
40,0
60,0
80,0
100,0
120,0
0,0 0,5 1,0 1,5 2,0 2,5 3,0
V (ILED-VNEG) [V]
I (ILED) [%
]
ILED (V bat=1.8V )
ILED (V bat=1.5V )
ILED (V bat=1.0V )
www.austriamicrosystems.com Revision 1.02 12 - 51
AS3400 AS3410 AS3 430 1v0
Data Sheet - Typical Operating Characteristics
Figure 10. THD vs. Frequency @ 1.5V, 16Ω, 25mW
Figure 11. Typical Performance Data, FF Configuration
www.austriamicrosystems.com Revision 1.02 13 - 51
AS3400 AS3410 AS3 430 1v0
Data Sheet - Detailed Description
8 Detailed Description
This section provides a detailed description of the device related components.
8.1 Audio Line Input
The chip features one line input. The blocks can work in mono differential or in stereo single ended mode.
In addition to the 12.5-25kΩ input impedance, LineIn has a termination resistor of 10kΩ which is also effective during MUTE to charge
eventually given input capacitors.
8.1.1 Gain Stage
The Line In gain stage is designed to have 63 gain steps of 0.75dB with a max gain of 0dB plus MUTE.
In default, the gain will be ramped up from MUTE to 0dB during startup. There is a possibility to make the playback volume user controlled by the
VOL pin with an ADC converted VOL voltage or UP/DN buttons.
In monitor mode, the gain stage can be set to an fixed default attenuation level for reducing the loudness of the music.
Figure 12. Line Inputs
8.1.2 Parameter
VBAT=1.5V, TA= 25ºC, unless otherwise specified.
Table 4. Line Input Parameter
Symbol Parameter Condition Min Typ Max Unit
VLIN Input Signal Level 0.6*
VBAT VBAT VPEAK
RLIN Input Impedance
0dB gain (12.5k // 10k) 5.6 kΩ
-46.5dB gain (25k // 10k) 7.2 kΩ
MUTE 10 kΩ
ΔRLIN Input Impedance Tolerance ±30 %
CLIN Input Capacitance 5pF
ALIN Programmable Gain -46.5 +0 dB
Gain Steps Discrete logarithmic gain steps 0.75 dB
Gain Step Accuracy 0.5 dB
ALINMUTE Mute Attenuation 100 dB
AGND
LINL
stereo mode
LINR
10k
10k
12.5k k
12.5k k
QLINR
QLINL
mute
mute
AGND
LINL
mono diff erent ial mode
LINR
10k
10k
12.5k k
12.5k k
QLINR
QLINL
mute
mute
AGND
www.austriamicrosystems.com Revision 1.02 14 - 51
AS3400 AS3410 AS3 430 1v0
Data Sheet - Detailed Description
8.2 Microphone Input
The AFE offers two microphone inputs and one low noise microphone voltage supply (microphone bias). The inputs can be switched to single
ended or differential mode.
Figure 13. Microphone Input
8.2.1 Gain Stage & Limiter
The Mic GainStage has programmable Gain within -6dB…+41.625dB in 128 steps of 0.375dB.
As soft-start function is implemented for an automatic gain ramping implemented with steps of 4ms to fade in the audio at the end of the start-up
sequence.
A limiter automatically attenuates high input signals. The AGC has 127 steps with 0.375dB with a dynamic range of the full gain stage.
In monitor mode, the gain stage can be set to an fixed (normally higher) gain level or be controlled by the VOL pin.
8.2.2 Supply
The MICS charge pump is providing a proper microphone supply voltage for the AAA supply. Since AAA batteries are operating down to 1.0V,
the direct battery voltage cannot be used for mic-supply. There are 2 modes.
The first mode SWITCH-MODE for 1.8V supply is to have just a switch from VBAT to MICS. With this switch, the microphone current is switched
off in idle mode.
The second mode CHAREGPUMP_MODE for AAA batteries is the real charge pump mode, in this mode a positive voltage is generated of about
2* VBAT.
It is also possible to switch off the microphone supply if not needed (e.g. playback without ANC)
ΔALIN Gain Ramp Rate
PotiMode, Tinit=100ms 20
ms/stepButtonMode, Tinit=400ms 80
MonitorMode 8
VATTACK Limiter Activation Level HPL/R start of neg. clipping VPEAK
VDECAY Limiter Release Level HPL/R VNEG
+0.3 VPEAK
tATTACK Limiter Attack Time 4µs
tDECAY Limiter Decay Time 8ms
Table 4. Line Input Parameter (Continued)
Symbol Parameter Condition Min Typ Max Unit
AGND
MICL
stereo mode
MICR
QMICR
QMICL
mono diff erent ial mode
AGND
MICL
MICR
QMICR
QMICL
AGND
www.austriamicrosystems.com Revision 1.02 15 - 51
AS3400 AS3410 AS3 430 1v0
Data Sheet - Detailed Description
8.2.3 Parameter
VBAT=1.5V, TA= 25ºC unless otherwise specified.
Table 5. Microphone Input Parameter
Symbol Parameter Condition Min Typ Max Unit
VMICIN0Input Signal Level AMIC = 30dB 20 mVP
VMICIN1A
MIC = 36dB 10 mVP
VMICIN2A
MIC = 42dB 5mVP
RMICIN Input Impedance MICP to AGND 7.5 kΩ
ΔMICIN Input Impedance Tolerance -7
+33 %
CMICIN Input Capacitance 5pF
AMIC Programmable Gain -6 +41.6 dB
Gain Steps Discrete logarithmic gain steps 0.375 dB
Gain Step Precision 0.15 dB
ΔAMIC Gain Ramp Rate Tinit=64ms 4 ms/step
VATTACK Limiter Activation Level VPEAK related to VBAT or VNEG 0.67 1
VDECAY Limiter Release Level 0.4 1
AMICLIMIT Limiter Gain Overdrive 127 @ 0.375dB 41.625 dB
tATTACK Limiter Attack Time 5µs/step
tDECAY-DEB Limiter Decay Debouncing Time 64 ms
tDECAY Limiter Decay Time 4ms/step
VMICS Microphone Supply Voltage VBAT*2-
240mV V
IMICSMIN Min. Microphone Supply Current
VBAT=+1.0V
VNEG=-0.7V
MICS=+1.75V
650 µA
ROUT_CP CP Output Resistance 1300 Ω
www.austriamicrosystems.com Revision 1.02 16 - 51
AS3400 AS3410 AS3 430 1v0
Data Sheet - Detailed Description
8.3 Headphone Output
The headphone output is a true ground output using VNEG as negative supply, designed to provide the audio signal with 2x12mW @ 16Ω-64Ω,
which are typical values for headphones. It is also capable to operate in bridged mode for higher impedance (e.g. 300Ω) headphone. In this
mode the left output is carrying the inverted signal of the right output shown in Figure 15.
Figure 14. Headphone Output Single Ended Mode
Figure 15. Headphone Output Differential Mode
8.3.1 Input Multiplexer
The signal from the line-input gain stage gets summed at the input of the headphone stage with the microphone gain stage output, the first filter
opamp output or the second filter opamp output. The microphone gain stage output is used per default. It is also possible to playback without
ANC by only using the line-input gain stage with no other signal on the multiplexer.
For the monitor mode, the setting of this input multiplexer can be changed to another source, normally to the microphone.
8.3.2 No-Pop Function
The No-Pop startup of the headphone stage takes 60ms to 120ms dependent on the supply voltage.
8.3.3 No-Clip Function
The headphone output stage gets monitored by comparator stages which detect if the output signal starts to clip.
This signal is used to reduce the LineIn gain to avoid distortion of the output signal. A hystereses avoids jumping between 2 gain steps for a
signal with constant amplitude.
Pop
Click
Control
HPR
HPL
AGND
LineInR
MUX
QOP2R
QOP1R
QMicR
LineInL
MUX
QOP2L
QOP1L
QMicL
HPVSS
HPVDD
open
open
LineIn
gai n st age