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Stereo CODEC with Speaker Driver
DESCRIPTION
The WM8976 is a low power, high quality CODEC designed
for portable applications such as multimedia phone, digital
still camera or digital camcorder.
The device integrates a preamp for differential microphone,
and includes drivers for speakers, headphone and
differential or stereo line output. External component
requirements are reduced as no separate microphone or
headphone amplifiers are required.
Advanced on-chip digital signal processing includes a 5-
band equaliser, a mixed signal Automatic Level Control for
the microphone or line input through the ADC as well as a
purely digital limiter function for record or playback.
Additional digital filtering options are available in the ADC
path, to cater for application filtering such as ‘wind noise
reduction’.
The WM8976 digital audio interface can operate as a master
or a slave. An internal PLL can generate all required audio
clocks for the CODEC from common reference clock
frequencies, such as 12MHz and 13MHz.
The WM8976 operates at analogue supply voltages from
2.5V to 3.3V, although the digital core can operate at
voltages down to 1.71V to save power. The speaker outputs
and OUT3/4 line outputs can run from a 5V supply if
increased output power is required. Individual sections of
the chip can also be powered down under software control.
WM8976
FEATURES
Stereo CODEC:
DAC SNR 98dB, THD -84dB (‘A’ weighted @ 48kHz)
ADC SNR 95dB, THD -84dB (‘A’ weighted @ 48kHz)
On-chip Headphone Driver with ‘capless’ option
- 40mW per channel into 16 / 3.3V SPKVDD
1W output power into 8 BTL speaker / 5V SPKVDD
- Capable of driving piezo speakers
- Stereo speaker drive configuration
Mic Preamps:
Differential or single-ended microphone interfaces
- Programmable preamp gain
- Pseudo differential input with common mode rejection
- Programmable ALC / Noise Gate in ADC path
Low-noise bias supplied for electret microphone
Other Features:
Enhanced 3-D function for improved stereo separation
Digital playback limiter
5-band Equaliser (record or playback)
Programmable ADC High Pass Filter (wind noise reduction)
Programmable ADC Notch Filter
Aux inputs for stereo analogue input signals or ‘beep’
On-chip PLL supporting 12, 13, 19.2MHz and other clocks
Support for 8, 11.025, 12, 16, 22.05, 24, 32, 44.1 and 48kHz
sample rates
Low power, low voltage
- 2.5V to 3.6V (digital: 1.71V to 3.6V)
5x5mm 32-lead QFN package
APPLICATIONS
Stereo Camcorder or DSC
Multimedia Phone
WOLFSON MICROELECTRONICS plc
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Production Data, November 2011, Rev 4.5
Copyright
2011
Wolfson Microelectronics plc
WM8976
TABLE OF CONTENTS
Production Data
TABLE OF CONTENTS ......................................................................................... 2
PIN CONFIGURATION .......................................................................................... 4
ORDERING INFORMATION .................................................................................. 4
PIN DESCRIPTION ................................................................................................ 5
ABSOLUTE MAXIMUM RATINGS ........................................................................ 6
RECOMMENDED OPERATING CONDITIONS ..................................................... 6
ELECTRICAL CHARACTERISTICS ..................................................................... 7
TERMINOLOGY .............................................................................................................. 9
SPEAKER OUTPUT THD VERSUS POWER ...................................................... 10
POWER CONSUMPTION .................................................................................... 11
AUDIO PATHS OVERVIEW ................................................................................ 13
SIGNAL TIMING REQUIREMENTS .................................................................... 14
SYSTEM CLOCK TIMING ............................................................................................. 14
AUDIO INTERFACE TIMING – MASTER MODE .......................................................... 14
AUDIO INTERFACE TIMING – SLAVE MODE ............................................................. 15
CONTROL INTERFACE TIMING – 3-WIRE MODE ...................................................... 16
CONTROL INTERFACE TIMING – 2-WIRE MODE ...................................................... 17
INTERNAL POWER ON RESET CIRCUIT .......................................................... 18
DEVICE DESCRIPTION ...................................................................................... 20
INTRODUCTION ........................................................................................................... 20
INPUT SIGNAL PATH ................................................................................................... 22
ANALOGUE TO DIGITAL CONVERTER (ADC) ........................................................... 28
INPUT LIMITER / AUTOMATIC LEVEL CONTROL (ALC)............................................ 32
OUTPUT SIGNAL PATH ............................................................................................... 44
3D STEREO ENHANCEMENT ...................................................................................... 51
ANALOGUE OUTPUTS ................................................................................................. 51
DIGITAL AUDIO INTERFACES ..................................................................................... 66
AUDIO SAMPLE RATES ............................................................................................... 71
MASTER CLOCK AND PHASE LOCKED LOOP (PLL) ................................................ 71
COMPANDING .............................................................................................................. 73
GENERAL PURPOSE INPUT/OUTPUT........................................................................ 75
OUTPUT SWITCHING (JACK DETECT)....................................................................... 76
CONTROL INTERFACE ................................................................................................ 77
RESETTING THE CHIP ................................................................................................ 78
POWER SUPPLIES....................................................................................................... 79
RECOMMENDED POWER UP/DOWN SEQUENCE .................................................... 80
POWER MANAGEMENT .............................................................................................. 84
REGISTER MAP .................................................................................................. 85
REGISTER BITS BY ADDRESS ................................................................................... 87
DIGITAL FILTER CHARACTERISTICS ............................................................ 103
TERMINOLOGY .......................................................................................................... 103
DAC FILTER RESPONSES ........................................................................................ 104
ADC FILTER RESPONSES ........................................................................................ 104
HIGHPASS FILTER ..................................................................................................... 105
5-BAND EQUALISER .................................................................................................. 106
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Production Data
WM8976
APPLICATION INFORMATION ......................................................................... 111
RECOMMENDED EXTERNAL COMPONENTS ......................................................... 111
PACKAGE DIAGRAM ....................................................................................... 112
IMPORTANT NOTICE ....................................................................................... 113
ADDRESS ................................................................................................................... 113
REVISION HISTORY ......................................................................................... 114
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WM8976
PIN CONFIGURATION
Production Data
ORDERING INFORMATION
ORDER CODE
WM8976CGEFL/V
WM8976CGEFL/RV
Note:
Reel quantity = 3,500
TEMPERATURE
RANGE
-25C to +85C
-25C to +85C
PACKAGE
32-lead QFN (5 x 5 mm)
(Pb-free)
32-lead QFN (5 x 5 mm)
(Pb-free, tape and reel)
MOISTURE
SENSITIVITY LEVEL
MSL3
MSL3
PEAK SOLDERING
TEMPERATURE
260 C
260 C
o
o
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Production Data
WM8976
PIN DESCRIPTION
PIN
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
NAME
LIP
LIN
L2/GPIO2
DNC
DNC
DNC
LRC
BCLK
ADCDAT
DACDAT
MCLK
DGND
DCVDD
DBVDD
CSB/GPIO1
SCLK
SDIN
MODE
AUXL
AUXR
OUT4
OUT3
ROUT2
SPKGND
LOUT2
SPKVDD
VMID
AGND
ROUT1
LOUT1
AVDD
MICBIAS
TYPE
Analogue input
Analogue input
Analogue input
Do not connect
Do not connect
Do not connect
Digital Input / Output
Digital Input / Output
Digital Output
Digital Input
Digital Input
Supply
Supply
Supply
Digital Input / Output
Digital Input
Digital Input / Output
Digital Input
Analogue input
Analogue input
Analogue Output
Analogue Output
Analogue Output
Supply
Analogue Output
Supply
Reference
Supply
Analogue Output
Analogue Output
Supply
Analogue Output
Mic Pre-amp positive input
Mic Pre-amp negative input
Line input/secondary mic pre-amp positive input/GPIO2 pin
Leave this pin floating
Leave this pin floating
Leave this pin floating
DAC and ADC Sample Rate Clock
Digital Audio Port Clock
ADC Digital Audio Data Output
DAC Digital Audio Data Input
Master Clock Input
Digital ground
Digital core logic supply
Digital buffer (I/O) supply
3-Wire Control Interface Chip Select / GPIO1 pin
3-Wire Control Interface Clock Input / 2-Wire Control Interface Clock
Input
3-Wire Control Interface Data Input / 2-Wire Control Interface Data Input
Control Interface Selection
Left Auxiliary input
Right Auxiliary input
Buffered midrail Headphone pseudo-ground, or Right line output or MONO
mix output
Buffered midrail Headphone pseudo-ground, or Left line output
Second right output, or BTL speaker driver positive output
Speaker ground (feeds speaker amp and OUT3/OUT4)
Second left output, or BTL speaker driver negative output
Speaker supply (feed speaker amp only)
Decoupling for ADC and DAC reference voltage
Analogue ground (feeds ADC and DAC)
Headphone or Line Output Right
Headphone or Line Output Left
Analogue supply (feeds ADC and DAC)
Microphone Bias
DESCRIPTION
Note:
It is recommended that the QFN ground paddle should be connected to analogue ground on the application PCB. Refer to
the application note WAN_0118 on “Guidelines on How to Use QFN Packages and Create Associated PCB Footprints”
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