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WM8742
24-bit 192kHz DAC with Advanced Digital Filtering
DESCRIPTION
The WM8742 is a very high performance stereo DAC designed for audio applications such as professional recording systems, A/V receivers and high specification CD, DVD and home theatre systems. The device supports PCM data input word lengths from 16 to 32-bits and sampling rates up to 192kHz. The WM8742 also supports DSD bitstream data format, in both direct DSD and PCM-converted DSD modes.
The WM8742 includes fine resolution volume and soft mute control, digital de-emphasis and a range of advanced digital filter responses, followed by a digital interpolation filter, multi-bit sigma delta modulator and stereo DAC. Wolfson’s patented architecture optimises the linearity of the DAC and provides maximum insensitivity to clock jitter.
The digital filters include several selectable roll-off and performance characteristics. The user can select between standard sharp or slow roll-off responses. In addition, the WM8742 includes a selection of advanced digital filter characteristics including non-half band filters and minimum phase filters.
This flexibility provides a range of benefits, such as significantly reduced pre-ringing and minimal group delay. The internal digital filters can also be by-passed and the WM8742 used with an external digital filter.
The WM8742 supports two connection schemes for audio DAC control. The 2/3 wire serial control interface provides access to all features. A range of features can also be accessed by hardware control interface.
The WM8742 is available in a convenient 28-SSOP package, and is pin compatible with the WM8740 and WM8741.
FEATURES
Advanced Ultra High Performance Multi-bit Sigma-Delta Architecture 126dB SNR (‘A’-weighted mono @ 48kHz) 123dB SNR (‘A’-weighted stereo @ 48kHz) 121dB SNR (non-weighted stereo @ 48kHz) -100dB THD @ 48kHz Differential analogue voltage outputs High tolerance to clock jitter
PCM Mode Sampling frequency: 32kHz to 192kHz Input data word length support: 16 to 32-bit Supports all standard audio interface formats Selectable advanced digital filter responses Includes linear/minimum phase and range of tailored characteristics Enables low pre-ringing, minimal latency Optional interface to industry standard external filters Digital volume control in 0.125dB steps with soft ramp and soft mute Anti-clipping mode to prevent distortion even with input signals recorded up to 0dB Selectable de-emphasis support Zero Flag output
DSD Mode DSD bit-stream support for SACD applications Support for normal or phase modulated bit-streams Direct or PCM converted DSD paths (DSD Plus) DSD mute
Hardware or software control modes: 2 and 3 wire serial control interface support
Pin compatible with WM8740 and WM8741 4.5V to 5.5V analogue, 3.15V to 3.6V digital supply
operation 28-lead SSOP Package
APPLICATIONS
Professional audio systems CD, DVD, SACD audio Home theatre systems A/V receivers
WOLFSON MICROELECTRONICS plc
Production Data, February 2013, Rev 4.3 Copyright 2013 Wolfson Microelectronics plc
PD, Rev 4.3, February 2013 2
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MCLK
AVDDR
AGNDR
AVDD AGND
PCM/DSD MUX
MUTEB/SDOUT MODE/LRSEL CSB/SADDR/I2S SDIN/DEEMPH SCLK/DSD ZFLAG DIFFHW
AVDDL AGNDL
WM8742 BLOCK DIAGRAM
Production Data
Production Data
WM8742
TABLE OF CONTENTS
DESCRIPTION....................................................................................................... 1 FEATURES ............................................................................................................ 1 APPLICATIONS..................................................................................................... 1 BLOCK DIAGRAM ................................................................................................ 2 TABLE OF CONTENTS......................................................................................... 3 PIN CONFIGURATION .......................................................................................... 4 ORDERING INFORMATION.................................................................................. 4 PIN DESCRIPTION (SOFTWARE CONTROL MODE).......................................... 5 PIN DESCRIPTION (HARDWARE CONTROL MODE)......................................... 7 ABSOLUTE MAXIMUM RATINGS ........................................................................ 9 THERMAL PERFORMANCE................................................................................. 9 RECOMMENDED OPERATING CONDITIONS................................................... 10 ELECTRICAL CHARACTERISTICS ................................................................... 10
MASTER CLOCK TIMING............................................................................................. 12 PCM DIGITAL AUDIO INTERFACE TIMINGS .............................................................. 12 DSD AUDIO INTERFACE TIMINGS..............................