w
DESCRIPTION
The WM8722 is a high performance stereo DAC designed
for audio applications such as digital TV and set top boxes.
The WM8722 has two stereo analogue outputs, one at line
level and one that includes a digitally controllable mute and
attenuator function. An on-chip tone generator can be
routed through the line or variable outputs.
WM8722 supports data input word lengths from 16-24 bits
and sampling rates up to 96kHz. The WM8722 consists of a
serial interface port, digital interpolation filter, multi-bit sigma
delta modulator and stereo DAC in a small 20-pin SSOP
package.
The 3 or 2-wire serial MPU compatible control port provides
access to all features including tone generation, on-chip
mute, attenuation and phase reversal.
The programmable data input port supports glueless
interfaces to popular DSPs, audio decoders and S/PDIF
and AES/EBU receivers.
WM8722
Stereo DAC with Integrated Tone Generator and Line/Variable
Level Outputs
FEATURES
•
Performance
−
−
−
•
102dB SNR (‘A’ weighted @48kHz)
-95dB THD
5V or 3V supply operation
−
Sampling frequency: 8kHz – 96kHz
3-wire or 2-wire serial MPU compatible interface for
−
Input data word; 16/20/24-Bit
−
−
−
Soft mute
De-emphasis
Volume control
•
•
•
On-chip tone generator (1Hz – 32kHz, 0.1 – 25.5s)
Stereo analogue inputs
20-pin SSOP package
APPLICATIONS
•
•
•
Digital TV
Digital broadcast receivers
Set top boxes
BLOCK DIAGRAM
MXINL
+12 to -34.5dB, 1.5dB Steps
4
MONO ATTENUATION CONTROL
+
DIN
BCKIN
LRCIN
SCKI
SERIAL
INTERFACE
DIGITAL
ATTENUATOR
AND
FILTERS
0/-6dB
LINEOUTL
MULTI
BIT
∑
∆
MULTI
BIT
SC
DAC
+
0/-6dB
VAROUTL
L Mix Switches (0-9)
R Mix Switches (0-9)
+6 to -73dB,
1dB Steps
MD
MC
LATCH
BUSY
CONTROL
INTERFACE
+
DIGITAL
ATTENUATOR
AND
FILTERS
0/-6dB
VAROUTR
MULTI
BIT
∑
∆
MULTI
BIT
SC
DAC
+
0/-6dB
LINEOUTR
TCLK
TONE
GENERATOR
TONE
DAC
0 TO -46.5dB, 1.5dB
STEPS
WM8722
+12 TO -34.5dB, 1.5dB
STEPS
DVDD DGND
AGND
CAP
AVDD MXINR
WOLFSON MICROELECTRONICS LTD
Advanced Information, June 2001, Rev 2.1
Copyright
2001
Wolfson Microelectronics Ltd.
w :: www.wolfsonmicro.com
WOLFSON [ WOLFSON MICROELECTRONICS PLC ]
