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WM9709

AC-link Interface Audio DAC

WOLFSON MICROELECTRONICS plc

w :: www.wolfsonmicro.com

Production Data, February 2003, Rev 1.3

Copyright

2003 Wolfson Microelectronics plc

DESCRIPTION

The WM9709 is a low cost, high-quality stereo audio DAC.

It utilises the Intel specified AC-link audio interface protocol,

allowing a pair of audio output channels to be added to any

AC link compliant controller device at minimal board area

and external component cost.

The WM9709 device supports 48ks/s sample rates when

operated at the normal AC link rate. The WM9709 supports

a revision 1.03 AC ’97 AC-link interface, the device acting

as a master in normal operation.

The ID pin can be used to select which data slots on the

AC-link are to be used as input to the DAC. This allows 3 x

WM9709 to be used with a single controller that supports 6

channel sound, to output surround sound audio signals.

When supporting surround, centre or LFE channels, the

WM9709 behaves as a slave device.

The WM9709 device is footprint compatible with the

WM9708 codec, allowing simple swapping between DAC

and full codec features on the same board. The WM9709 is

packaged in a 20-pin SSOP.

FEATURES

•

20-Bit Stereo DAC

•

Audio Performance

−

102dB SNR (‘A’ weighted at 48kHz)

−

-95dB THD

•

Revision 1.03 or higher AC’97 AC-link interface support.

•

3.3V or mixed 3V digital, 5V analogue operation

•

20-Pin SSOP Package

•

Minimal external component cost

•

Support for surround and centre/LFE channels

APPLICATIONS

•

Notebook PC

•

PC sound cards

•

Motherboards

•

Custom sound applications

BLOCK DIAGRAM

LINEOUTR

SERIAL

INTERFACE

SDATAOUT

LINEOUTL

SIGMA

DELTA

MODULATOR

SDATAIN

BITCLK

SIGMA

DELTA

MODULATOR

DIGITAL FILTERS

DVDD

AGND

DGND

LOW

PASS

FILTER

LOW

PASS

FILTER

CAP

RIGHT

DAC

LEFT

DAC

AGND

AVDD

SYNC

RESETB

XTLIN XTLOUT

ID

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WM9709