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a

AD7729

One Technology Way, P.O. Box 9106, Norwood, MA 02062-9106, U.S.A.

Tel: 781/329-4700

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© Analog Devices, Inc., 1998

Dual Sigma-Delta ADC

with Auxiliary DAC

FUNCTIONAL BLOCK DIAGRAM

ASDI

ASDIFS

ASCLK

ASDO

ASDOFS

ASE

BSDI

BSDIFS

BSCLK

BSDO

BSDOFS

BSE

MCLK

RxON

RESETB

REFERENCE

DECIMATION

FIR DIGITAL

FILTER

10-BIT

AUXDAC

OFFSET

ADJUST

DECIMATION

FIR DIGITAL

FILTER

BASEBAND

SERIAL

INTERFACE

AUXILIARY

SERIAL

INTERFACE

AUXDAC

IRxP

IRxN

QRxP

QRxN

REFCAP

REFOUT

AVDD2

AVDD1

DGND

DVDD1

DVDD2

AGND

OFFSET

ADJUST

MODULATOR

MODULATOR

DIVIDE BY 2

MUX

FEATURES

+3 V Supply Voltage

Baseband Serial Port (BSPORT)

Differential IRx and QRx

ADC Channels

Two 15-Bit Sigma-Delta A/D Converters

FIR Digital Filters

64 dB SNR

Output Word Rate 270.83 kHz

Twos Complement Coding

On-Chip Offset Calibration

Power-Down Mode

Auxiliary D/A Converter

Auxiliary Serial Port (ASPORT)

On-Chip Voltage Reference

Low Power

28-Lead TSSOP/28-Lead SOIC

APPLICATIONS

GSM Basestations

Pagers

GENERAL DESCRIPTION

This monolithic 3 V CMOS device is a low power, two-channel,

input port with signal conditioning. The receive path is com-

posed of two high performance sigma-delta ADCs with digital

filtering. A common bandgap reference feeds the ADCs.

A control DAC is included for such functions as AFC. The auxil-

iary functions can be accessed via the auxiliary port (ASPORT).

This device is available in a 28-lead TSSOP package or a

28-lead SOIC package.