WM8740
24-bit, High Performance 192kHz Stereo DAC
Advanced Information, July 2000, Rev 1.7
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
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•
•
•
•
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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:
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Hardware mode: mute, de-emphasis, audio format
control
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Serial mode: mute, de-emphasis, attenuation (256
steps), phase reversal
Fully differential voltage outputs
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APPLICATIONS
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CD, DVD audio
Home theatre systems
Professional audio systems
BLOCK DIAGRAM
MODE ML/I2S MC/DM1 MD/DM0 DIFFHW MUTEB CSBIWO RSTB ZERO MODE8X AGNDR AVDDR
(22) (21)
(24)
(28)
(27)
(26)
(6)
(25)
(23)
(4)
(10) (9)
WM8740
CONTROL INTERFACE
(11) VMIDR
SCLK (5)
BCKIN (3)
LRCIN (1)
DIN (2)
SERIAL
INTERFACE
MUTE/
ATTEN
DIGITAL
FILTERS
MUX
SIGMA
DELTA
MODULATOR
RIGHT
DAC
LOW
PASS
FILTER
(12) VOUTRP
(13) VOUTRN
MUX
MUTE/
ATTEN
SIGMA
DELTA
MODULATOR
LEFT
DAC
LOW
PASS
FILTER
(17) VOUTLP
(16) VOUTLN
(18) VMIDL
(15)
(8)
AVDD DVDD
(20) (19)
(14)
AVDDL. AGNDL AGND
(7)
DGND
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
.
WOLFSON [ WOLFSON MICROELECTRONICS PLC ]
