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24-Bit, 192kHz Stereo ADC
DESCRIPTION
The WM8786 is a stereo audio ADC with differential inputs
designed for high performance recordable media applications.
Data is provided as a PCM output.
Stereo 24-bit multi-bit sigma-delta ADCs are used with digital
audio output word lengths of 16 to 32 bits, and sampling rates
from 8kHz to 192kHz. The device also has a high pass filter to
remove residual DC offsets.
The device is hardware controlled. Pin programming provides
access to all features including oversampling rate, audio format,
powerdown, master/slave
control
and digital
signal
manipulation. The device is supplied in a 20-lead SSOP
package.
WM8786
FEATURES
•
•
•
•
•
•
•
•
SNR 111dB (‘A’ weighted @ 48kHz)
THD -102dB (at -0.1dB)
Sampling Frequency: 8 – 192kHz
Hardware Control Interface
Master or Slave Clocking Mode
Programmable Audio Data Interface Modes
- I
2
S, Left, Right Justified or DSP
- 24-Bit Word Length
Supply Voltages
- Analogue 4.5 to 5.5V
- Digital core: 2.7V to 3.6V
20-lead SSOP package
APPLICATIONS
•
•
•
•
Recordable DVD Players
Personal Video Recorders
High End Sound Cards
Studio Audio Processing Equipment
BLOCK DIAGRAM
WOLFSON MICROELECTRONICS plc
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Production Data, February 2008, Rev 4.3
Copyright
©2008
Wolfson Microelectronics plc
WM8786
TABLE OF CONTENTS
Production Data
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
ELECTRICAL CHARACTERISTICS ......................................................................6
TERMINOLOGY ............................................................................................................ 7
SIGNAL TIMING REQUIREMENTS .......................................................................8
SYSTEM CLOCK TIMING ............................................................................................. 8
AUDIO INTERFACE TIMING – MASTER MODE, PCM DATA ...................................... 8
AUDIO INTERFACE TIMING – SLAVE MODE, PCM DATA ......................................... 9
POWER-ON RESET ................................................................................................... 10
DIGITAL FILTER CHARACTERISTICS ...............................................................11
TERMINOLOGY .......................................................................................................... 11
HIGH PASS FILTER TRANSFER CHARACTERISTIC................................................ 11
FILTER RESPONSES ..........................................................................................12
DEVICE DESCRIPTION.......................................................................................16
INTRODUCTION ......................................................................................................... 16
DIGITAL AUDIO INTERFACE ..................................................................................... 16
AUDIO INTERFACE CONTROL.................................................................................. 19
OVERSAMPLING RATIOS AND SIGMA-DELTA MODULATOR FREQUENCY.......... 19
MASTER CLOCK AND AUDIO SAMPLE RATES........................................................ 20
MLCK AND LRCLK PHASE RELATIONSHIP.............................................................. 20
APPLICATIONS INFORMATION .........................................................................21
RECOMMENDED EXTERNAL COMPONENTS .......................................................... 21
RECOMMENDED PCB LAYOUT ................................................................................ 22
PACKAGE DIMENSIONS ....................................................................................23
IMPORTANT NOTICE ..........................................................................................24
ADDRESS: .................................................................................................................. 24
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Production Data
WM8786
PIN CONFIGURATION
AINL+
AINL-
VREFGND
AVDD
AGND
LRCLK
DOUT
BCLK
MCLK
MS0
1
2
3
4
5
6
7
8
9
10
20
19
18
17
16
15
14
13
12
11
AINR+
AINR-
VREF
VMID
DGND
DVDD
OSR1
OSR0
AUDIOF1
AUDIOF0
ORDERING INFORMATION
ORDER CODE
WM8786GEDS/V
TEMPERATURE
RANGE
-40°C to +85°C
PACKAGE
20-lead SSOP
(Pb-free)
20-lead SSOP,
(Pb-free, tape and reel)
MOISTURE SENSITIVITY
LEVEL
MSL3
PEAK SOLDERING
TEMPERATURE
260
o
C
WM8786GEDS/RV
-40°C to +85°C
MSL3
260
o
C
Note:
Reel quantity = 2,000
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PD Rev 4.3 February 2008
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WM8786
PIN DESCRIPTION
PIN
1
2
3
4
5
6
7
8
9
10
NAME
AINL+
AINL-
VREFGND
AVDD
AGND
LRCLK
DOUT
BCLK
MCLK
MS0
(pull down pad)
AUDIOF0
AUDIOF1
TYPE
Analogue Input
Analogue Input
Analogue Reference
Supply
Supply
Digital Input / Output
Digital Output
Digital Input / Output
Digital Input
Digital Input
DESCRIPTION
Left Channel Positive Input
Left Channel Negative Input
Negative Reference Connection
Analogue Supply
Analogue Ground (return path for AVDD)
Audio Interface Left / Right Clock
ADC Digital Audio Data
Audio Interface Bit Clock
Master Clock
Production Data
Master/Slave Control
0 = Slave Mode Audio Interface
1 = Master Mode Audio Interface @ 256fs (or @128fs in quad rate)
Audio Format Selection
00 = 24 bit right justified audio data format
01 = 24 bit left audio data format
10 = I
2
S audio data format
11 = DSP audio data format
Oversampling Rate Control
00 = Single rate (48kHz)
01 = Dual rate (96kHz)
10 = Quad rate (192kHz)
11 = Not valid
Digital Supply
Digital Ground (return path for DVDD)
Midrail Voltage Decoupling Capacitor
Reference Voltage Decoupling Capacitor
Right Channel Negative Input
Right Channel Positive Input
11
12
Digital Input
Digital Input
13
14
OSR0
(pull down pad)
OSR1
Digital Input
Digital Input
15
16
17
18
19
20
DVDD
DGND
VMID
VREF
AINR-
AINR+
Supply
Supply
Analogue Output
Analogue Reference
Analogue Input
Analogue Input
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Production Data
WM8786
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
Digital supply voltage
Analogue supply voltage
Voltage range digital inputs
Voltage range analogue inputs
Master Clock Frequency
Operating temperature range, T
A
Storage temperature after soldering
Notes
1. Analogue and digital grounds must always be within 0.3V of each other.
-40°C
-65°C
MIN
-0.3V
-0.3V
DGND -0.3V
AGND -0.3V
MAX
+3.63V
+7V
DVDD + 0.3V
AVDD +0.3V
40MHz
+85°C
+150°C
RECOMMENDED OPERATING CONDITIONS
PARAMETER
Digital supply range
Analogue supply range
Ground
SYMBOL
DVDD
AVDD
DGND,AGND
TEST
CONDITIONS
MIN
2.7
4.5
0
TYP
MAX
3.6
5.5
UNIT
V
V
V
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