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Mono CODEC with Speaker Driver
DESCRIPTION
The WM8974 is a low power, high quality mono CODEC
designed for portable applications such as Digital Still Camera
or Digital Voice Recorder.
The device integrates support for a differential or single ended
mic, and includes drivers for speakers or headphone, and
mono line output. External component requirements are
reduced as no separate microphone or headphone amplifiers
are required.
Advanced Sigma Delta Converters are used along with digital
decimation and interpolation filters to give high quality audio at
sample rates from 8 to 48ks/s. Additional digital filtering
options are available in the ADC path, to cater for application
filtering such as ‘wind noise reduction’, plus an advanced
mixed signal ALC function with noise gate is provided. The
digital audio interface supports A-law and
µ-law
companding.
An on-chip PLL is provided to generate the required Master
Clock from an external reference clock. The PLL clock can
also be output if required elsewhere in the system.
The WM8974 operates at supply voltages from 2.5 to 3.6V,
although the digital supplies can operate at voltages down to
1.71V to save power. The speaker and mono outputs use a
separate supply of up to 5V which enables increased output
power if required. Different sections of the chip can also be
powered down under software control by way of the selectable
two or three wire control interface.
WM8974 is supplied in a very small 4x4mm QFN package,
offering high levels of functionality in minimum board area,
with high thermal performance.
WM8974
FEATURES
•
•
•
•
•
•
•
•
•
Mono CODEC:
Audio sample rates:8, 11.025, 16, 22.05, 24, 32, 44.1, 48kHz
DAC SNR 98dB, THD -84dB (‘A’-weighted @ 8 – 48ks/s)
ADC SNR 94dB, THD -83dB (‘A’-weighted @ 8 – 48ks/s)
On-chip Headphone/Speaker Driver with ‘cap-less’ connect
- 40mW output power into 16Ω / 3.3V SPKVDD
- BTL speaker drive 0.9W into 8Ω / 5V SPKVDD
Additional MONO Line output
Multiple analog or ‘Aux’ inputs, plus analog bypass path
Mic Preamps:
Differential or single end Microphone Interface
- Programmable preamp gain
- Psuedo differential inputs with common mode rejection
- Programmable ALC / Noise Gate in ADC path
Low-noise bias supplied for electret microphones
•
OTHER FEATURES
•
5 band EQ (record or playback path)
•
Digital Playback Limiter
•
Programmable ADC High Pass Filter (wind noise reduction)
•
Programmable ADC Notch Filter
•
On-chip PLL
•
Low power, low voltage
- 2.5V to 3.6V (digital: 1.71V to 3.6V)
- power consumption <10mA all-on 48ks/s mode
•
4x4x0.9mm 24 lead QFN package
APPLICATIONS
•
•
•
•
Digital Still Camera Audio Codec
Wireless VoIP and other communication device handsets /
headsets
Portable audio recorder
General Purpose low power audio CODEC
WOLFSON MICROELECTRONICS plc
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Production Data, Rev 4.5, September 2008
Copyright
©2008
Wolfson Microelectronics plc
WM8974
TABLE OF CONTENTS
Production Data
DESCRIPTION .......................................................................................................1
FEATURES.............................................................................................................1
APPLICATIONS .....................................................................................................1
TABLE OF CONTENTS .........................................................................................2
PIN CONFIGURATION...........................................................................................3
ORDERING INFORMATION ..................................................................................3
PIN DESCRIPTION ................................................................................................4
ABSOLUTE MAXIMUM RATINGS.........................................................................5
RECOMMENDED OPERATING CONDITIONS .....................................................5
ELECTRICAL CHARACTERISTICS ......................................................................6
TERMINOLOGY ............................................................................................................ 8
SIGNAL TIMING REQUIREMENTS .......................................................................9
SYSTEM CLOCK TIMING ............................................................................................. 9
AUDIO INTERFACE TIMING – MASTER MODE .......................................................... 9
AUDIO INTERFACE TIMING – SLAVE MODE............................................................ 10
CONTROL INTERFACE TIMING – 3-WIRE MODE .................................................... 11
CONTROL INTERFACE TIMING – 2-WIRE MODE .................................................... 12
DEVICE DESCRIPTION.......................................................................................13
INTRODUCTION ......................................................................................................... 13
INPUT SIGNAL PATH ................................................................................................. 14
ANALOGUE TO DIGITAL CONVERTER (ADC).......................................................... 19
INPUT LIMITER / AUTOMATIC LEVEL CONTROL (ALC) .......................................... 23
OUTPUT SIGNAL PATH ............................................................................................. 35
ANALOGUE OUTPUTS............................................................................................... 42
OUTPUT SWITCH ...................................................................................................... 47
DIGITAL AUDIO INTERFACES................................................................................... 49
AUDIO SAMPLE RATES ............................................................................................. 54
MASTER CLOCK AND PHASE LOCKED LOOP (PLL) ............................................... 55
GENERAL PURPOSE INPUT/OUTPUT...................................................................... 57
CONTROL INTERFACE.............................................................................................. 57
RESETTING THE CHIP .............................................................................................. 58
POWER SUPPLIES .................................................................................................... 58
POWER MANAGEMENT ............................................................................................ 63
REGISTER MAP...................................................................................................65
REGISTER BITS BY ADDRESS ................................................................................. 66
DIGITAL FILTER CHARACTERISTICS ...............................................................77
TERMINOLOGY .......................................................................................................... 77
DAC FILTER RESPONSES......................................................................................... 78
ADC FILTER RESPONSES......................................................................................... 78
DE-EMPHASIS FILTER RESPONSES........................................................................ 79
HIGHPASS FILTER..................................................................................................... 80
5-BAND EQUALISER .................................................................................................. 81
APPLICATIONS INFORMATION .........................................................................85
RECOMMENDED EXTERNAL COMPONENTS .......................................................... 85
PACKAGE DIAGRAM ..........................................................................................86
IMPORTANT NOTICE ..........................................................................................87
ADDRESS: .................................................................................................................. 87
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Production Data
WM8974
PIN CONFIGURATION
TOP VIEW
ORDERING INFORMATION
ORDER CODE
WM8974GEFL/V
WM8974GEFL/RV
Note:
Reel Quantity = 3,500
TEMPERATURE
RANGE
-40°C to +85°C
-40°C to +85°C
PACKAGE
24-lead QFN (4x4x0.9mm)
(Pb-free)
24-lead QFN (4x4x0.9mm)
(Pb-free, tape and reel)
MOISTURE SENSITIVITY
LEVEL
MSL3
MSL3
PACKAGE BODY
TEMPERATURE
260
o
C
260
o
C
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WM8974
PIN DESCRIPTION
PIN NO
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
NAME
MICBIAS
AVDD
AGND
DCVDD
DBVDD
DGND
ADCDAT
DACDAT
FRAME
BCLK
MCLK
CSB/GPIO
SCLK
SDIN
MODE
MONOOUT
SPKOUTP
SPKGND
SPKOUTN
SPKVDD
AUX
VMID
MICN
MICP
Supply
Supply
Supply
Supply
Supply
Digital Output
Digital Input
Digital Input / Output
Digital Input / Output
Digital Input
Digital Input / Output
Digital Input
Digital Input / Output
Digital Input
Analogue Output
Analogue Output
Supply
Analogue Output
Supply
Analogue Input
Reference
Analogue Input
Analogue Input
TYPE
Analogue Output
Microphone bias
Analogue supply (feeds ADC and DAC)
Analogue ground (feeds ADC and DAC)
Digital core supply
Digital buffer (input/output) supply
Digital ground
ADC digital audio data output
DAC digital audio data input
DAC and ADC sample rate clock or frame synch
Digital audio port clock
Master clock input
DESCRIPTION
Production Data
3-Wire MPU chip select or general purpose input/output pin.
3-Wire MPU clock Input / 2-Wire MPU Clock Input
3-Wire MPU data Input / 2-Wire MPU Data Input
Control interface mode selection pin.
Mono output
Speaker output positive
Speaker ground (feeds speaker and mono output amps only)
Speaker output Negative
Speaker supply (feeds speaker and mono output amps only)
Auxiliary analogue input
Decoupling for midrail reference voltage
Microphone negative input
Microphone positive input (common mode)
Note:
It is recommended that the QFN ground paddle should be connected to analogue ground on the application PCB.
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Production Data
WM8974
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
DBVDD, DCVDD, AVDD supply voltages
SPKVDD supply voltage
Voltage range digital inputs
Voltage range analogue inputs
Operating temperature range, T
A
Storage temperature prior to soldering
Storage temperature after soldering
Notes
1.
2.
Analogue and digital grounds must always be within 0.3V of each other.
All digital and analogue supplies are completely independent from each other.
MIN
-0.3V
-0.3V
DGND -0.3V
AGND -0.3V
-40°C
-65°C
MAX
+4.2
+7V
DVDD +0.3V
AVDD +0.3V
+85°C
+150°C
30°C max / 85% RH max
RECOMMENDED OPERATING CONDITIONS
PARAMETER
Digital supply range (Core)
Digital supply range (Buffer)
Analogue supplies range
Speaker supply
Ground
Notes
1.
2.
3.
4.
5.
When using PLL, DCVDD must be 1.9V or higher.
AVDD must be
≥
DCVDD.
DBVDD must be
≥
DCVDD.
In non-boosted mode, SPKVDD must be
≥
AVDD, if boosted SPKVDD must be
≥
1.5x AVDD.
When using PLL, DCVDD must be
≥
1.9V.
SYMBOL
DCVDD
DBVDD
AVDD
SPKVDD
DGND,AGND,SPKGND
TEST CONDITIONS
MIN
1.71
1.71
2.5
2.5
0
TYP
MAX
3.6
3.6
3.6
5.5
UNIT
V
V
V
V
V
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