WM8740

24-bit, High Performance 192kHz Stereo DAC

Advanced Information, July 2000, Rev 1.7

WOLFSON MICROELECTRONICS LTD

Lutton Court, Bernard Terrace, Edinburgh, EH8 9NX, UK

Tel: +44 (0) 131 667 9386

Fax: +44 (0) 131 667 5176

Email: sales@wolfson.co.uk

http://www.wolfson.co.uk

Advanced Information data sheets contain

preliminary data on new products in the

preproduction phase of development.

Supplementary data will be published at a

later date.

2000 Wolfson Microelectronics Ltd

.

DESCRIPTION

The WM8740 is a very high performance stereo DAC

designed for audio applications such as CD, DVD, home

theatre systems, set top boxes and digital TV. The WM8740

supports data input word lengths from 16 to 24-bits and

sampling rates up to 192kHz. The WM8740 consists of a

serial interface port, digital interpolation filter, multi-bit sigma

delta modulator and stereo DAC in a small 28-pin SSOP

package. The WM8740 also includes a digitally controllable

mute and attenuator function on each channel.

The

internal

digital

filter

has

two

selectable

roll-off

characteristics. A sharp or slow roll-off can be selected

dependent on application requirements. Additionally, the

internal digital filter can be by-passed and the WM8740

used with an external digital filter.

The WM8740 supports two connection schemes for audio

DAC

control.

The

SPI-compatible

serial

control

port

provides access to a wide range of features including on-

chip mute, attenuation and phase reversal. A hardware

controllable interface is also available.

FEATURES

•

120dB SNR (‘A’ weighted mono @48kHz), THD+N: -104dB

@ FS

•

117dB SNR (‘A’ weighted stereo @48kHz), THD+N: -104dB

@ FS

•

Sampling frequency: 8kHz to 192kHz

•

Selectable digital filter roll-off

•

Optional interface to industry standard external filters

•

Differential mono mode needing no glue logic

•

Input data word: 16 to 24-bit

•

Hardware or SPI compatible serial port control modes:

•

Hardware mode: mute, de-emphasis, audio format

control

•

Serial mode: mute, de-emphasis, attenuation (256

steps), phase reversal

•

Fully differential voltage outputs

APPLICATIONS

•

CD, DVD audio

•

Home theatre systems

•

Professional audio systems

BLOCK DIAGRAM

SERIAL

INTERFACE

MUTE/

ATTEN

CONTROL INTERFACE

BCKIN (3)

(12) VOUTRP

SIGMA

DELTA

MODULATOR

LRCIN (1)

DIN (2)

AGNDR

(10)

AVDDR

(9)

MUTE/

ATTEN

SIGMA

DELTA

MODULATOR

DIGITAL

FILTERS

MODE8X

(4)

MUX

(8)

DVDD

(15)

AVDD

(14)

AGND

(7)

DGND

MUTEB

(25)

DIFFHW

(6)

MD/DM0

(26)

MC/DM1

(27)

ML/I2S

(28)

MODE

(24)

CSBIWO

(23)

RSTB

(22)

ZERO

(21)

LOW

PASS

FILTER

LOW

PASS

FILTER

(11) VMIDR

MUX

(18) VMIDL

RIGHT

DAC

LEFT

DAC

(19)

AGNDL

(20)

WM8740

SCLK (5)

(16) VOUTLN

(13) VOUTRN

(17) VOUTLP