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a
AD7729
One Technology Way, P.O. Box 9106, Norwood, MA 02062-9106, U.S.A.
Tel: 781/329-4700 World Wide Web Site: http://www.analog.com
Fax: 781/326-8703 © 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
AVDD2AVDD1DGNDDVDD1DVDD2 AGND
OFFSET
ADJUST
SD
MODULATOR
SD
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.