WM9001GEFL - Wolfson Microelectronics

w WM9001

1W Dual-Mode Class AB/D Speaker Driver

WOLFSON MICROELECTRONICS plc

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Production Data, March 2010, Rev 4.1

DESCRIPTION

The WM9001 is a powerful, high quality speaker driver which

can operate in class D or AB mode, providing total flexibility to

the system designer. Low leakage, high PSRR and pop/click

suppression enable direct battery connection to the speaker

supply. RF noise suppression techniques and differential design

are used to suppress undesired noise. A single-ended input

option has been included for complete system flexibility.

The device is enabled by setting a logic '1' on the EN pin. The

class D clock can be generated by an internal oscillator, or

supplied from an external clock source.

Flexible speaker boost options (requiring no additional

components) allow output volume to be maximised for various

SPKVDD/AVDD combinations while minimising internal power

consumption.

The WM9001 is available in a 3x3mm QFN package, ideal for

portable systems such as mobile phones, portable navigation

devices, media players, laptop computers and electronic

dictionaries.

FEATURES

• Class D and AB speaker driver modes for flexibility

• Speaker driver provides 1W into 8Ω at <0.1% THD

• SNR 102dB (Class AB), 97dB (Class D)

• Differential and single-ended input modes

• >80dB PSRR @ 217Hz (SPKVDD)

• <1μA typical leakage with direct battery connection

• Filterless speaker connection

• Fully differential architecture (differential mode)

• Pop/click suppression

• RF noise suppression

• Fully compatible with Wolfson CODECs

including WM8990 / WM8991

• Internal oscillator or external clock source

• Thermal shutdown protection

• 3x3mm QFN package

APPLICATIONS

• Mobile phones

• Portable navigation devices

• Portable media players

• Laptop computers and portable gaming devices

• Electronic dictionaries

• General-purpose high quality speaker amplifier

BLOCK DIAGRAM

WM9001 Production Data

PD, March 2010, Rev 4.1

TABLE OF CONTENTS

DESCRIPTION ....................................................................................................... 1

FEATURES..... ................ ............... ................ ................ ................ ................ ......... 1

APPLICATIONS ..................................................................................................... 1

BLOCK DIAGRAM ................................................................................................. 1

TABLE OF CONTENTS ......................................................................................... 2

PIN CONFIGURATION ... ............... ................ .................... ................ ................ ..... 3

ORDERING INFORMATION .................................................................................. 3

PIN DESCRIPTION ................................................................................................ 4

ABSOLUTE MAXIMUM RATINGS ......................................................................... 5

RECOMMENDED OPERATING CONDITIONS ..................................................... 5

THERMAL PERFORMANCE ................................................................................. 6

POWER DE-RATING ............................................................................................. 7

ELECTRICAL CHARACTERISTICS ...................................................................... 8

TERMINOLOGY ...... .......... .......... ............. ......... .......... .......... .......... .......... ......... .......... .. 9

TYPICAL POWER CONSUMPTION .................................................................... 10

SPEAKER DRIVER PERFORMANCE ................................................................. 11

CLASS D MODE .......................................................................................................... 11

CLASS AB MODE ........................................................................................................ 11

PSRR PERFORMANCE ....................................................................................... 12

EFFICIENCY ........................................................................................................ 13

AUDIO SIGNAL PATHS ....................................................................................... 14

DEVICE DESCRIPTION ....................................................................................... 15

INTRODUCTION .......................................................................................................... 15

POWER ON RESET .................................................................................................... 15

ENABLE ....................................................................................................................... 15

INPUT SIGNAL PATH .................................................................................................. 16

SYNC ........................................................................................................................... 16

SPEAKER DRIVER MODE SELECT ............................................................................ 17

SIGNAL BOOST CONTROL ........................................................................................ 17

THERMAL SHUTDOWN .............................................................................................. 18

RF NOISE SUPPRESSION .......................................................................................... 18

POPS / CLICK SUPPRESSION ................................................................................... 18

APPLICATIONS INFORMATION ......................................................................... 19

TYPICAL STAND-ALONE USAGE ............................................................................... 19

TYPICAL USAGE WITH WM8991 CODEC ................................................................. 20

SPEAKER SELECTION ............................................................................................... 21

PCB LAYOUT CONSIDERATIONS .............................................................................. 22

RECOMMENDED EXTERNAL COMPONENTS ........................................................... 23

PACKAGE DIMENSIONS .................................................................................... 24

IMPORTANT NOTICE .......................................................................................... 25

ADDRESS .................................................................................................................... 25

Production Data WM9001

w PD, March 2010, Rev 4.1

PIN CONFIGURATION

The WM9001 is supplied in a 3mm x 3mm 16 pin QFN package

QFN

ORDERING INFORMATION

DEVICE MINIMUM ORDER

QUANTITY

TEMPERATURE

RANGE

PACKAGE MOISTURE

SENSITIVITY LEVEL

PEAK SOLDERING

TEMPERATURE

QFN

WM9001GEFL

164 -40°C to 85°C QFN MSL 1 260°C

QFN

WM9001GEFL/R

3500 -40°C to 85°C QFN MSL 1 260°C

WM9001 Production Data

PD, March 2010, Rev 4.1

PIN DESCRIPTION

PIN NO NAME TYPE DESCRIPTION

16 INP_SEL Digital Input Audio Input Mode Select

15 LIP Analogue Input Positive differential input

14 EN Enable Device Enable input

13 LIN Analogue Input Negative differential input

12 BSEL2 Digital Input Signal Boost Control[2]

11 BSEL1 Digital Input Signal Boost Control[1]

10 BSEL0 Digital Input Signal Boost Control[0]

9 VMID Analogue Output Midrail voltage decoupling capacitor

8 AVDD Supply Analogue supply

7 CDMODE Digital In Class AB/D Mode select

6 AGND Supply Analogue supply ground

5 SYNC Digital Input Class D clock input

4 VOUTN Analogue Output Speaker negative output

3 SPKGND Supply Speaker driver supply ground

2 SPKVDD Supply Speaker driver supply

1 VOUTP Analogue Output Speaker positive output

Production Data WM9001

w PD, March 2010, Rev 4.1

ABSOLUTE MAXIMUM RATINGS

Absolute Maximum Ratings are stress ratings only. Permanent damage to the device may be caused by continuously

operating at or beyond these limits. Device functional operating limits and guaranteed performance specifications are given

under Electrical Characteristics at the test conditions specified.

ESD Sensitive Device. This device is manufactured on a CMOS process. It is therefore generically susceptible

to damage from excessive static voltages. Proper ESD precautions must be taken during handling and storage

of this device.

Wolfson tests its package types according to IPC/JEDEC J-STD-020B for Moisture Sensitivity to determine acceptable storage

conditions prior to surface mount assembly. These levels are:

MSL1 = unlimited floor life at <30°C / 85% Relative Humidity. Not normally stored in moisture barrier bag.

MSL2 = out of bag storage for 1 year at <30°C / 60% Relative Humidity. Supplied in moisture barrier bag.

MSL3 = out of bag storage for 168 hours at <30°C / 60% Relative Humidity. Supplied in moisture barrier bag.

The Moisture Sensitivity Level for each package type is specified in Ordering Information.

CONDITION MIN MAX

AVDD -0.3V +4.5V

SPKVDD -0.3V +7V

Digital Inputs voltage range AGND -0.3V AVDD +0.3V

Analogue Inputs voltage range AGND -0.3V AVDD +0.3V

Operating temperature range, TA -40ºC +85ºC

Junction temperature, TJ -40ºC +150ºC

Storage temperature after soldering -65ºC +150ºC

RECOMMENDED OPERATING CONDITIONS

PARAMETER SYMBOL MIN TYP MAX UNIT

Analogue supply AVDD 2.7 3.6 V

Speaker supply SPKVDD 2.7 5.5 V

Ground AGND, SPKGND 0 V

Notes:

1. Analogue and speaker grounds must always be within 0.3V of each other.

2. All supplies are completely independent from each other (i.e. not internally connected).

3. AVDD must be less than or equal to SPKVDD.

4. SPKVDD must be high enough to support the peak output voltage when using DCGAIN and ACGAIN functions, to

avoid output waveform clipping. Peak output voltage is AVDD*(DCGAIN+ACGAIN)/2.

5. The EN and SYNC pins are compatible with low voltage (eg. 1.8v) logic levels from external devices, and can accept

logic 1 digital inputs as low as 1.6V, even though the WM9001 AVDD supply minimum is 2.7V. This provides

compatibility with a low voltage DVDD on a controlling device such as the WM8991 CODEC.

WM9001 Production Data

PD, March 2010, Rev 4.1

THERMAL PERFORMANCE

Thermal analysis should be performed in the intended application to prevent the WM9001 from

exceeding maximum junction temperature. Several contributing factors affect thermal performance

most notably the physical properties of the mechanical enclosure, location of the device on the PCB

in relation to surrounding components and the number of PCB layers. Connecting the GND

pins/paddle through thermal vias and into a large ground plane will aid heat extraction.

Three main heat transfer paths exist to surrounding air:

- Package top to air (radiation).

- Package bottom to PCB (radiation).

- Package pins/paddle/balls to PCB (conduction).

The temperature rise TR is given by TR = PD * ӨJA

- PD is the power dissipated in the device.

- ӨJA is the thermal resistance from the junction of the die to the ambient temperature

and is therefore a measure of heat transfer from the die to surrounding air. ӨJA is

determined with reference to JEDEC standard JESD51-9.

The junction temperature TJ is given by TJ = TA +TR, where TA is the ambient temperature.

PARAMETER SYMBOL MIN TYP MAX UNIT

Operating temperature range TA -40 85 °C

Operating junction temperature TJ -40 100 °C

Thermal Resistance ӨJA 52 °C/W

Production Data WM9001

w PD, March 2010, Rev 4.1

POWER DE-RATING

The speaker driver has been designed to drive a maximum of 1W into 8Ω with a 5V supply.

However, thermal restrictions defined by the package ӨJA limit the amount of power that can be

safely dissipated in the device without exceeding the maximum operating junction temperature.

Power dissipated in the device correlates directly with speaker efficiency, hence there are separate

de-rating curves for class D and class AB operation.

Under no circumstances should the recommended maximum powers be exceeded.

The de-rating curves in Figure 1 are based on a sinusoidal input signal delivering a maximum output

power of 1W into 8Ω.

CLASS D

CLASS AB

[W]

[ºC]

807060

0.4

0.6

0.8

1.0

SPKVDD = 2.7V

SPKVDD = 3V

SPKVDD = 3.3V

SPKVDD = 3.6V

SPKVDD = 4.2VSPKVDD = 5VSPKVDD = 5.5V

0.9

0.7

0.3

0.5

0.1

0.2

55 65 75 85

Figure 1 Speaker Power De-Rating Curves

WM9001 Production Data

PD, March 2010, Rev 4.1

ELECTRICAL CHARACTERISTICS

Test Conditions

AVDD = 3.3V; SPKVDD = 5V, TA = +25oC, 1kHz input signal, BSEL[2:0] = 000 unless otherwise stated.

PARAMETER TEST CONDITIONS MIN TYP MAX UNIT

Analogue Input Pins (LIN, LIP)

Maximum Full-Scale Input Signal Level

Differential Mode (INP_SEL=0): This is

the maximum on each input pin; the total

differential input is 2x this figure.

Single-Ended Mode (INP_SEL=1): This is

the maximum on LIP.

Note that the maximum signal level scales

in proportion to AVDD (AVDD/3.3).

1.0

Vrms

dBV

Input Resistance – Differential Mode

(INP_SEL=0)

Gain=0dB (BSEL[2:0]=000) 160 kΩ

Gain=2.1dB (BSEL[2:0]=001) 123 kΩ

Gain=2.9dB (BSEL[2:0]=010) 112 kΩ

Gain=3.6dB (BSEL[2:0]=011) 103 kΩ

Gain=4.5dB (BSEL[2:0]=100) 94 kΩ

Gain=5.1dB (BSEL[2:0]=101) 87 kΩ

Input Resistance – Single-Ended Mode

(INP_SEL=1)

All gain settings 20 kΩ

Input Capacitance 10 pF

Speaker Driver Performance

SNR (A-weighted) BSEL[2:0] = 011 (1.52x)

8Ω Bridge Tied Load

Class D Mode

Differential and Single-Ended

Input Modes

90 97 dB

THD (PO=0.5W) -92 -81 dB

THD+N (PO=0.5W) -87 -79 dB

THD (PO=1.0W) -83 -73 dB

THD+N (PO=1.0W) -78 -68 dB

SNR (A-weighted) BSEL[2:0] = 011 (1.52x)

8Ω Bridge Tied Load

Class AB Mode

Differential and Single-Ended

Input Modes

94 102 dB

THD (PO=0.5W) -79 -70 dB

THD+N (PO=0.5W) -77 -68 dB

THD (PO=1.0W) -77 -70 dB

THD+N (PO=1.0W) -75 -68 dB

Mute Attenuation Device disabled (EN=0) 100 dB

Common Mode Rejection Ratio Differential Mode 50 dB

Bandwidth 0 22 kHz

AVDD PSRR 100mV pk-pk ripple, 217Hz 60 dB

SPKVDD PSRR 83 dB

DC Offset at load 5 mV

SPKVDD Leakage Current EN=0 0.3 μA

AVDD Leakage Current EN=0 9 μA

Reference Levels

VMID Midrail Reference Voltage -3% AVDD/2 +3% V

Output Common Mode Voltage

(Note: BSEL[2:0]=110 and BSEL[2:0]=111

are reserved settings)

BSEL[2:0] = 000 1.00 x VMID V

BSEL[2:0] = 001 1.27 x VMID

BSEL[2:0] = 010 1.40 x VMID

BSEL[2:0] = 011 1.52 x VMID

BSEL[2:0] = 100 1.67 x VMID

BSEL[2:0] = 101 1.80 x VMID

Production Data WM9001

w PD, March 2010, Rev 4.1

Test Conditions

AVDD = 3.3V; SPKVDD = 5V, TA = +25oC, 1kHz input signal, BSEL[2:0] = 000 unless otherwise stated.

PARAMETER TEST CONDITIONS MIN TYP MAX UNIT

Input / Output (for hardware control)

Input HIGH Level (BSEL, CDMODE) 0.7×AVDD V

Input HIGH Level (EN, SYNC) 1.6 V

Input LOW Level 0.3×AVDD V

Input capacitance 10 pF

Input leakage -0.9 0.9 uA

Oscillator

Free-running oscillator frequency 600 800 950 kHz

External clock frequency range 600 800 950 kHz

Power-Up Time (Based on recommended Vmid capacitor value; these times will vary with different capacitors)

Class AB Enable time Vmid capacitor = 4.7μF 400 ms

Class D Enable time Vmid capacitor = 4.7μF 100 ms

TERMINOLOGY

1. Signal-to-Noise Ratio (dB) – SNR is a measure of the difference in level between the maximum theoretical full scale

output signal and the output with no input signal applied.

2. Total Harmonic Distortion (dB) – THD is the level of the rms value of the sum of harmonic distortion products relative

to the amplitude of the measured output signal.

3. Total Harmonic Distortion plus Noise (dB) – THD+N is the level of the rms value of the sum of harmonic distortion

products plus noise in the specified bandwidth relative to the amplitude of the measured output signal.

4. All performance measurements carried out with 20kHz low pass filter, and where noted an A-weighted filter. Failure to

use such a filter will result in higher THD and lower SNR readings than are found in the Electrical Characteristics. The

low pass filter removes out of band noise; although it is not audible it may affect dynamic specification values.

5. Mute Attenuation – This is a measure of the difference in level between the full scale output signal and the output with

mute applied.

WM9001 Production Data

PD, March 2010, Rev 4.1

TYPICAL POWER CONSUMPTION

MODE GAIN EN CDMODE SYNC INP_SEL TOTAL

(V) (uA) (V) (uA) (uW)

OFF 0dB0000002.70.020.054

EN=0, AVDD=0V 0dB0000003.70.060.222

0dB0000004.20.110.462

0dB00000050.140.7

0dB0000005.50.170.935

(V) (uA) (V) (uA) (uW)

OFF Standby 0dB 00002.77.672.70.0220.763

EN=0, AVDD enabled 2.1dB000038.163.70.0724.739

2.1dB00003.38.914.20.129.823

3.6dB00003.38.9350.3731.319

3.6dB00003.69.755.50.6438.62

(V) (mA) (V) (mA) (mW)

Class AB Speaker Mode 0dB 11002.70.32.73.4510.12

8Ω2.1dB110030.333.74.6918.35

2.1dB11003.30.354.25.624.71

3.6dB11003.30.3556.3733

3.6dB11003.60.385.57.4242.16

Class D Speaker Mode 0dB10002.71.092.71.085.84

8Ω2.1dB100031.223.71.529.3

Internal Oscillator 2.1dB10003.31.364.21.812.06

3.6dB10003.31.3652.1515.23

3.6dB10003.61.55.52.4218.74

Class D Speaker Mode 0dB 1 0 800kHz 0 2.7 1.08 2.7 1.13 5.97

8Ω2.1dB 1 0 800kHz 0 3 1.23 3.7 1.54 9.4

External Oscillator 2.1dB 1 0 800kHz 0 3.3 1.37 4.2 1.76 11.91

3.6dB 1 0 800kHz 0 3.3 1.37 5 2.19 15.45

3.6dB 1 0 800kHz 0 3.6 1.52 5.5 2.47 19.06

(V) (mA) (V) (mA) (mW)

Class AB Speaker Mode

0.45W into 8Ω

Class AB Speaker Mode

0.2W into 8Ω

Class D Speaker Mode

1W into 8Ω

Class D Speaker Mode

0.5W into 8Ω

606.73

1180.18

3.6dB10003.31.365120.45

722.26

3.6dB10003.31.345235.15

1059.3

3.6dB11003.30.355144.22

3.3 0.35 5 211.63

QUIESCENT

ACTIVE

3.6dB1100

AVDD SPKVDD

BATTERY LEAKAGE

STANDBY LEAKAGE

Note that the Gain settings are determined by the BSEL[2:0] values as follows:

Gain (dB) Gain (v) BSEL[2] BSEL[1] BSEL[0]

0dB 1.00x 0 0 0

2.1dB 1.27x 0 0 1

2.9dB 1.40x 0 1 0

3.6dB 1.52x 0 1 1

4.5dB 1.67x 1 0 0

5.1dB 1.80x 1 0 1

Production Data WM9001

w PD, March 2010, Rev 4.1

SPEAKER DRIVER PERFORMANCE

The THD+N performance of the Speaker Driver is shown below for Class AB mode and for Class D mode.

Load RL = 8Ω + 22μH, Frequency = 1kHz.

Data is provided for four typical Power Supply /Gain combinations:

AVDD SPKVDD GAIN

2.7V 2.7V 0 dB (x1.0)

3.0V 3.7V 2.1 dB (x1.27)

3.3V 4.2V 2.1 dB (x1.27)

3.3V 5.0V 3.6 dB (x1.52)

CLASS D MODE

WM9001 THD+N Ratio v Output Power

Cla ss D

0.001

0.01

0.1

0 0.2 0.4 0.6 0.8 1 1.2 1.4

Output Power (W)

THD+N Ratio (%)

SPKVDD=5.0V, AVDD=3.3V, Gain=3.6dB SPKVDD=4.2V, AVDD=3.3V, Gain=2.1dB

SPKVDD=3.7V, AVDD=3.0V, Gain=2.1dB SPKVDD=2.7V, AVDD=2.7V, Gain=0dB

Figure 2 Class D Speaker Performance

CLASS AB MODE

WM9001 THD+N Ratio v Output Power

Class AB

0.001

0.01

0.1

0 0.2 0.4 0.6 0.8 1 1.2 1.4 1.6

Output Power (W)

THD+N Ratio (%)

SPKVDD=5.0V, AVDD=3.3V, Gain=3.6dB SPKVDD=4.2V, AVDD=3.3V, Gain=2.1dB

SPKVDD=3.7V, AVDD=3.0V, Gain=2.1dB SPKVDD=2.7V, AVDD=2.7V, Gain=0dB

Figure 3 Class AB Speaker Performance

WM9001 Production Data

PD, March 2010, Rev 4.1

PSRR PERFORMANCE

Typical PSRR versus frequency curves are provided below. The curves were produced by

superimposing a 100mV pk-pk ripple onto a DC level at the supply pin and measuring rejection of

this signal at the output.

CLASS AB SPKVDD PSRR CLASS D SPKVDD PSRR

WM9001 Class AB SPKVDD PSRR

AVDD=3.3V, SPKVDD=5.0V

100

0 2 4 6 8 101214 161820

Frequency (kHz)

PSRR (dB)

Differential Mode

Single-Emded Mode

WM9001 Class D SPKVDD PSRR

AVDD=3.3V, SPKVDD=5.0V

100

0 2 4 6 8 10121416 1820

Frequency (kHz)

PSRR (dB)

Differential Mode

Single-Emded Mode

CLASS AB AVDD PSRR CLASS D AVDD PSRR

WM9001 Class AB AVDD PSRR

AVDD=3.3V, SPKVDD=5.0V

02468101214161820

Frequency (kHz)

PSRR (dB)

Differential Mode

Single-Emded Mode

WM9001 Class D AVDD PSRR

AVDD=3.3V, SPKVDD=5.0V

02468101214161820

Frequency (kHz)

PSRR (dB)

Differential Mode

Single-Emded Mode

Note: The measurement noise floor is at approximately 88dB

Production Data WM9001

w PD, March 2010, Rev 4.1

EFFICIENCY

Typical Efficiency versus output power curves are provided below for both class AB and class D

modes.

CLASS AB CLASS D

WM9001 Class AB Efficiency

AVDD=3.3V, SPKVDD=5.0V, BSEL[2:0]=011 (x1.52)

100

0 200 400 600 800 1000 1200 1400

Output Powe r (mW )

Efficiency (%)

Differential Mode

Single-Ended Mode

WM9001 Class D Efficiency

AVDD=3.3V, SPKVDD=5.0V, BSEL[2:0]=011 (x1.52)

100

0 200 400 600 800 1000 1200 1400

Output Power (mW)

Efficiency (%)

Differential Mode

Single-Ended Mode

WM9001 Production Data

PD, March 2010, Rev 4.1

AUDIO SIGNAL PATHS

The WM9001 speaker driver can operate in two modes:

1. INP_SEL=0: Takes a differential audio input and produces a differential class AB or class D

output. The audio signal path is illustrated below.

Figure 4 Differential Mode Audio Signal Paths

2. INP_SEL=1: Takes a single-ended audio input and produces a differential class AB or class D

output. The audio signal path is illustrated below.

Figure 5 Single-Ended Mode Audio Signal Paths

Production Data WM9001

w PD, March 2010, Rev 4.1

DEVICE DESCRIPTION

INTRODUCTION

The WM9001 is a powerful mono speaker driver, which can operate in class D or AB mode, providing

total flexibility to the system designer. The WM9001 can deliver 1W in class D mode, Figure 2 , or in

class AB mode, Figure 3, into an 8Ω load. The input can be configured either as a single channel

differential line output offering good noise rejection characteristics, or as a single-ended line output

for systems where there is no differential option.

It can be used as a stand-alone device, or in conjunction with a CODEC such as the WM8991 or

WM8990 to provide a complete stereo solution. The gain settings and speaker driver mode are

configurable via the hardware control pins BSEL[2:0] and CDMODE. For stand-alone operation these

pins are tied to logic 1/0.

The class D amplifier requires a clock signal. An internal oscillator can be used for stand alone

operation by tying the SYNC pin to logic 1/0. Alternatively an external clock can be used by applying

this signal to the SYNC pin. The EN (Enable) pin provides a controllable method for switching

ON/OFF the speaker outputs.

The very small 3 x 3mm QFN packages make the WM9001 ideal for portable systems, such as

mobile phones, portable navigation devices, media players, laptop computers and electronic

dictionaries.

POWER ON RESET

The WM9001 includes an internal Power-On Reset (POR) circuit which is used to reset the device

into a default state at power up. The POR circuit is controlled by the AVDD power supply. Note that

there is no POR on the SPKVDD supply.

When the chip is powered down, the speaker driver outputs, SPKP and SPKN, become tri-state.

ENABLE

The chip is enabled by a logic ‘1’ on the EN pin.

PIN NAME DESCRIPTION

EN Device Enable input

0 = Device Disabled

1 = Device Enabled

Table 1 Device Enable Control

The EN pin should be used to disable the device prior to removing the audio or clock (removing an

external clock will not disable the output). When the chip is disabled, the speaker driver outputs

become tri-state.

The EN pin is compatible with low voltage (eg. 1.8v) logic levels from external devices, and can

accept logic 1 digital inputs as low as 1.6V, even though the WM9001 AVDD supply minimum is

2.7V. This provides compatibility with a low voltage DVDD on a controlling device such as the

WM8991 CODEC.

Ultra low quiescent current in the disabled state minimises extends battery life in this condition. The

typical values of SPKVDD current and AVDD current in the disabled (Standby) state are described in

the Electrical Characteristics section.

WM9001 Production Data

PD, March 2010, Rev 4.1

INPUT SIGNAL PATH

The line inputs to the WM9001 are identified as LIP and LIN on the pin diagram. These are a fully

balanced differential input pair, with matched impedances on both terminals. The input stage of the

WM9001 is driven by the voltage difference between these two pins. This results in a very low noise

amplifier stage, as any common mode noise (unwanted signals that are present in equal amplitude

on both pins) are cancelled out at the input and are not reproduced at the output.

The LIP input can also be configured as a single-ended line input – see Table 2 below. Single-ended

to differential conversion is carried out internally with the N channel input (normally LIN) connected to

an inverted version of the P channel (LIP). In this configuration the LIN pin should be connected to

analogue ground.

PIN NAME DESCRIPTION

16 INP_SEL

Input Mode Select

0 = Differential Mode (LIP/LIN)

1 = Single-Ended Mode (LIP only)

Table 2 Input Mode Control

WM9001 inputs LIP and LIN are biased to Vmid (equal to AVDD/2) therefore DC-blocking capacitors

are required when connecting non Vmid reference input signals. The Vmid pin must be decoupled

externally – see ‘Applications Information’ for more detail.

SYNC

In Class D operation the WM9001 may be clocked using one of two methods.

• Externally supplied clock to the SYNC pin (800kHz typical).

• Internal oscillator, allowing stand-alone operation of the device.

The Clock source selection is determined automatically by the WM9001 according to the status of

the SYNC pin. If a clock signal is present on the SYNC pin, then this signal is automatically selected

as the WM9001 clock source. If the clock signal is interrupted and this pin is pulled high or low, then

the internal oscillator will be selected. It is not recommended to interrupt or change clock sources

whilst the device is enabled.

PIN NAME DESCRIPTION

5 SYNC

Class D PWM clock input

Constant 0 / 1 – Internal Oscillator enabled

Clock – Clock used to sync PWM class D

Table 3 Sync Clock Control

The SYNC pin is compatible with low voltage (eg. 1.8v) logic levels from external devices, and can

accept logic 1 digital inputs as low as 1.6V, even though the WM9001 AVDD supply minimum is

2.7V. This provides compatibility with a low voltage DVDD on a controlling device such as the

WM8991 CODEC.

Figure 6 System Clock Timing Requirements

Please refer to the Electrical Characteristics for minimum and maximum SYNC frequencies.

Production Data WM9001

w PD, March 2010, Rev 4.1

SPEAKER DRIVER MODE SELECT

The speaker outputs operate in a BTL configuration, in either class AB or class D mode. The speaker

driver mode is selected using the CDMODE pin.

PIN NAME DESCRIPTION

7 CDMODE

Class AB/D Mode Select

0 = Class D mode

1 = Class AB mode

Table 4 Class AB / D Mode Control

SIGNAL BOOST CONTROL

Six levels of signal boost are available to provide maximum output power for many commonly used

SPKVDD/AVDD combinations. These boost options are available in class AB and class D modes.

AC and DC gain levels from 1.0x to 1.8x are selected using the BSEL[2:0] input pins. Note that

ACGAIN = DCGAIN for all settings.

An appropriate SPKVDD supply voltage must be provided to prevent waveform clipping when signal

boost is used.

Figure 7 Signal Boost Operation

PIN NAME DESCRIPTION

12,11,10 BSEL[2:0]

Signal Boost Control

000 = 1.00x boost (+0dB)

001 = 1.27x boost (+2.1dB)

010 = 1.40x boost (+2.9dB)

011 = 1.52x boost (+3.6dB)

100 = 1.67x boost (+4.5dB)

101 = 1.8x boost (+5.1dB)

110 = Reserved

111 = Reserved

Table 5 Signal Boost Control

To prevent pop noise, the BSEL[2:0] settings should not be modified while the speaker outputs are

enabled. Note that ACGAIN = DCGAIN for all settings.

WM9001 Production Data

PD, March 2010, Rev 4.1

THERMAL SHUTDOWN

To protect the WM9001 from damage due to overheating, a thermal shutdown circuit is included. If

the junction temperature exceeds approximately 150ºC, then the WM9001 will be disabled.

Note that the internal power dissipation of the WM9001 is significantly higher in class AB mode than

in class D mode – see “Power De-Rating” section.

It is not possible to disable the thermal shutdown function.

RF NOISE SUPPRESSION

The WM9001 provides internal RF filtering which minimises the impact of high frequency noise in the

system.

POPS / CLICK SUPPRESSION

The WM9001 incorporates mechanisms that reduce audible pops/clicks at the speaker outputs.

To prevent pop noise, it is recommended that the BSEL, SYNC, CDMODE and INP_SEL settings

should not be modified while the speaker outputs are enabled. Muting the device (setting EN = 0)

during any update to these settings is recommended.

Production Data WM9001

w PD, March 2010, Rev 4.1

APPLICATIONS INFORMATION

TYPICAL STAND-ALONE USAGE

The WM9001 may be used as a differential speaker amplifier, as illustrated in Figure 8, or as a

single-ended speaker amplifier in Figure 9.

Figure 8 Operation of WM9001 as Stand-alone Differential Amplifier

Figure 9 Operation of WM9001 as a Stand-alone Single-ended Amplifier

In the both configurations DC blocking capacitors are required on the input paths. A typical

application might use 1uF capacitors for this purpose, providing a high pass cut-off frequency of less

than 20Hz.

In single-ended mode it is recommend that the unused LIN input is connected to analogue ground.

WM9001 Production Data

PD, March 2010, Rev 4.1

TYPICAL USAGE WITH WM8991 CODEC

The WM9001 may be used in conjunction with a CODEC such as the WM8991 to provide a complete

stereo solution. Such a solution allows the left and right drivers to be positioned separately as close

to the speakers as possible, minimising EMI emissions from long speaker cables.

In this configuration the EN & SYNC pins may be driven from GPIO outputs from the WM8991, and,

providing that the WM8991 and WM9001 are connected to the same analogue supply (AVDD), then

DC blocking capacitors are not required on the LIP and LIN inputs to WM9001.

CONTROL

INTERFAC E

SDIN

SCLK

ADCDAT

ADCLRC/GPIO1

BCLK

DACDAT

DACLRC

MODE

CSB/ADDR

GPIO5/DACDAT2

GPIO6/ADCLRCB

DIGITAL AUDIO

INTERFAC E

A-law and u-law s upport

TDM Support

DCVDD

DBVDD

DGND

SPKGND

SPKVDD

HPVDD

HPGND

GPIO 2/MC LK2

GPIO 3/BC LK2

GPIO4/DACLRC2

MCLK

PLL SY SCLK

MCLK 2

MCLK

Left ADC Bypass

Left MIC

Left Line Input to Left Output Mixer

Rx Voice -

Left Line Input to Speaker

Right Line Input to Speaker

Rx Voice +

Right Line Input to Right Output Mixer

Right MIC

Right ADC Bypass

INPUT PGAs INPUT MIXERS

DIGITAL CORE

GPIO

Alternative DAC Inter face

Alternative MCLK

Button Control / Accessory Detect

Clock Output

Inverted ADCLRC

MICBIAS

50k

VREF

AVDD

AGND

VMID

LIN2

LIN1

RIN1

LIN3/GPI7

RIN3 /GPI 8

RIN2

LIN4/RXN

RIN4 /RXP

INMIXR

LIN12

LIN34

RIN3 4

RIN12

AINLMUX

AINR MUX

250k

5k5k

MICBIAS Current Dete ct

-73dB to +6dB,

1dB steps

-73dB to +6dB,

1dB steps

LIN2

Mixer L

DAC L

DAC R

Mixer R

RIN2

LIN3

L MIC

R MIC

R ADC Bypass

L ADC Bypass

DAC L

DAC R

R ADC Bypass

L ADC Bypass

L MIC

R MIC

RIN3

Mixer R

RXP

RXN

Mix er L

MIC L

MIC R

Mix er L

Mixer R

MIC L

MIC R

Inver ted Out R

Mixer L

Mixer R

Inver ted Out L

OUTPUT MIXERS

LOPGA

ROPGA

HIGH PAS S

FILTER

(Voice or Hi-

Fi)

HIGH PASS

FILTER

(Voice or Hi-

Fi)

0dB,

+6dB,

+12dB,

+18dB

ADC L

ADC R

MON

MIX

-71.625dB to

+17.625dB,

0.375dB steps

-71.625dB to

+17.625dB,

0.375dB

steps

-71.625dB to 0dB,

0.375dB steps

-71.625dB to 0dB,

0.375dB steps

-36dB to 0dB,

3dB steps

-12dB to 0dB,

3dB steps

-12dB to 0dB,

3dB steps

0dB, +30dB

-12dB to +6dB

0dB, +30dB

-12dB to +6dB

-16.5dB to +30dB, 0.75dB steps

-16.5dB to +30dB, 0. 75dB steps

-16.5dB to +30dB, 0.75dB steps

DIFFINL

DIFF INR

OUT3 MIX

OUT4MIX

ROPMIX

RONMIX

LONMIX

LOPMIX

DAC L

DAC R

INMIXL

POR

AVDD

DCVDD

POR

-12dB to +6dB

RXVOICE

-12dB to +6dB

-12dB to +6dB RXVOICE

RIN3

LIN3

LOMIX

ROMI X

Record R

Record L

LADC

bypass

RADC

bypass

Mixer L

Mixer R

SPKMIX

0dB,

-6dB,

-12dB

LOUT

OUT3

OUT4

LON

LOP

ROP

RON

-73dB to +6dB, 1dB steps

HP ROUT

-73dB to +6dB, 1dB steps

Line

0dB,

-6dB

0dB, -6dB

SPKP

SPKN

1x,

1.27x

1.4x,

1.52x

1.67x

1.8x

1xVMID,

1.27xVMID,

1.4xVMID,

1.52xVMID,

1.67xVMID

1.8xVMID

SPKPGA

-73dB to +6dB,

1dB steps

DIFFERENTIAL RIGHT CHANNEL SPEAKER OUTPUT

LEFT CHANNEL

SPEAKER OUTPUT

ACGAIN & DCGAIN

SET BY

REGISTERS

ACGAIN & DCGAIN

SET BY H/W

SYNC

CDMODE

SET BY H/W

LIN

LIP

AVDD

CLASS AB/D

SPEAKER DRIVER

-SPKN

SPKP

AGND SPKVDD SPKGND

POP/ CLICK

SUPPR ESS ION

OSCILLATOR

THERMAL

SHUTDOWN

VMID

CDMODE SYNCBSEL[ 2:0]

D / AB Selec t

CLOCK

DETECT

DEVICE

ENABLE

AGN

AVDD

ACGAIN

DCGAIN

RF NOISE

SUPPR ESSI ON

OUTPUT POWER

BOOST SEL ECT

INP_SEL

Figure 10 Operation of WM9001 in Conjunction with WM8991

The EN and SYNC pins are compatible with low voltage (eg. 1.8v) logic levels from external devices,

and can accept logic 1 digital inputs as low as 1.6V, even though the WM9001 AVDD supply

minimum is 2.7V. This provides compatibility with a low voltage DVDD on a controlling device such

as the WM8991 CODEC.

Production Data WM9001

w PD, March 2010, Rev 4.1

SPEAKER SELECTION

In Class D driver mode, the WM9001 output contains high frequency signals resulting from the

switched PWM operation. To avoid the need for specific filter components, it is important to make an

appropriate choice of loudspeaker. Note that, for Class AB mode usage, the choice of speaker is not

so important as there are no high frequency harmonics in the WM9001 output.

The speaker inductance and load resistance create a low-pass filter which, ideally, will attenuate the

high frequency Class D switching harmonics whilst passing the desired audio frequencies. The 3dB

cut-off frequency of the speaker inductance and resistance may be calculated as follows:

fc = RL / 2πL

Therefore, for an 8Ω speaker and a desired 3dB cut-off frequency of 20kHz, the speaker should be

chosen to have an inductance of:

L = RL / 2πfc = 8Ω / 2π * 20kHz = 64μH

8Ω speakers for portable applications typically have an inductance in the range 20μH to 100μH. If the

inductance is higher than value calculated above, then the cut-off frequency will be reduced, limiting

the audio bandwidth. Lower values of inductance will result in a higher cut-off frequency. The Class D

outputs contain harmonics at much higher frequencies than is recommended for most speakers, and

the cut-off frequency of the filter must therefore be low enough to protect the speaker.

Figure 11 Speaker Equivalent Circuit

WM9001 Production Data

PD, March 2010, Rev 4.1

PCB LAYOUT CONSIDERATIONS

The efficiency of the speaker drivers is affected by the series resistance between the WM9001 and

the speaker (e.g. inductor ESR) as shown in Figure 12. This resistance should be as low as possible

to ٛaximizi efficiency.

Figure 12 Speaker Connection Losses

The distance between the WM9001 and the speakers should be kept to a minimum to reduce series

resistance, and also to reduce EMI. Further reductions in EMI can be achieved by additional passive

filtering and/or shielding as shown in Figure 13. When additional passive filtering is used, low ESR

components should be chosen to ٛaximizi series resistance between the WM9001 and the speaker,

ٛaximizing efficiency.

LC passive filtering will usually be effective at reducing EMI at frequencies up to around 30MHz. To

reduce emissions at higher frequencies, ferrite beads placed as close to the device as possible will

be more effective.

WM9001

SPKP

SPKN EMI WM9001

SPKP

SPKN

Short connection reduces EMI

WM9001

SPKP

SPKN

LC Filtering

reduces EMI

LOW ESR

WM9001

SPKP

SPKN

Shielding using PCB ground

plane (or Vdd) reduces EMI

WM9001

SPKP

SPKN

Ferrite beads reduce EMI

LC filtering is more effective at removing EMI at

frequencies below ~30MHz

Ferrite beads are more effective at removing

EMI at frequencies above ~30MHz

Long, exposed tracks emit more EMI

Figure 13 EMI Reduction Techniques

Production Data WM9001

w PD, March 2010, Rev 4.1

RECOMMENDED EXTERNAL COMPONENTS

WM9001 Production Data

PD, March 2010, Rev 4.1

PACKAGE DIMENSIONS

DM053.C

FL: 16 PIN QFN PLASTIC PACKAGE 3 X 3 X 0.75 mm BODY, 0.50 mm LEAD PITCH

INDEX AREA

(D/2 X E/2)

TOP VIEW

NOTES:

1. DIMENSION b APPLIES TO METALLIZED TERMINAL AND IS MEASURED BETWEEN 0.15 mm AND 0.30 mm FROM TERMINAL TIP.

2. FALLS WITHIN JEDEC, MO-220, VARIATION VGGD-2.

3. ALL DIMENSIONS ARE IN MILLIMETRES.

4. THE TERMINAL #1 IDENTIFIER AND TERMINAL NUMBERING CONVENTION SHALL CONFORM TO JEDEC 95-1 SPP-002.

5. COPLANARITY APPLIES TO THE EXPOSED HEAT SINK SLUG AS WELL AS THE TERMINALS.

6. REFER TO APPLICATIONS NOTE WAN_0118 FOR FURTHER INFORMATION REGARDING PCB FOOTPRINTS AND QFN PACKAGE SOLDERING.

7. THIS DRAWING IS SUBJECT TO CHANGE WITHOUT NOTICE.

Exposed lead

Dimensions (mm)

Symbols

MIN NOM MAX NOTE

0.70 0.75 0.80

0.05

0.02

0.20 REF

0.300.20

3.00 BSC

1.751.701.65

0.50 BSC

0.325 0.375 0.425

3.00 BSC

1.751.701.65

0.10

aaa

bbb

ccc

REF:

0.15

0.10

JEDEC, MO-220, VARIATION VGGD-2.

Tolerances of Form and Position

0.25

DETAIL 1

DETAIL 2

BCbbb MA

BOTTOM VIEW

Caaa

2 X

Caaa

2 X

SEATING PLANE DETAIL 2

C0.08

Cccc

SIDE VIEW

EXPOSED

GROUND

PADDLE

DETAIL 1

0.32mm

degrees

EXPOSED

GROUND

PADDLE

Datum

DETAIL 2

Terminal

Tip

e/2

SEE DETAIL 2

Production Data WM9001

w PD, March 2010, Rev 4.1

IMPORTANT NOTICE

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delivery and payment supplied at the time of order acknowledgement.

Wolfson warrants performance of its products to the specifications in effect at the date of shipment. Wolfson reserves the

right to make changes to its products and specifications or to discontinue any product or service without notice. Customers

should therefore obtain the latest version of relevant information from Wolfson to verify that the information is current.

Testing and other quality control techniques are utilised to the extent Wolfson deems necessary to support its warranty.

Specific testing of all parameters of each device is not necessarily performed unless required by law or regulation.

In order to minimise risks associated with customer applications, the customer must use adequate design and operating

safeguards to minimise inherent or procedural hazards. Wolfson is not liable for applications assistance or customer

product design. The customer is solely responsible for its selection and use of Wolfson products. Wolfson is not liable for

such selection or use nor for use of any circuitry other than circuitry entirely embodied in a Wolfson product.

Wolfson’s products are not intended for use in life support systems, appliances, nuclear systems or systems where

malfunction can reasonably be expected to result in personal injury, death or severe property or environmental damage. Any

use of products by the customer for such purposes is at the customer’s own risk.

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