REV. A

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a

AD974

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., 1999

4-Channel, 16-Bit, 200 kSPS

Data Acquisition System

FUNCTIONAL BLOCK DIAGRAM

CONTROL LOGIC

&

CALIBRATION CIRCUITRY

PWRD

V1A

V1B

BIP

CAP

REF

EXT/

INT

DATACLK

R/

C

CS

SYNC

DGND

BUSY

WR2

WR1

A1

A0

AGND2

AGND1

REF

BUFF

2.5V

REFERENCE

AD974

4 TO 1

MUX

+

LATCH

EN

V2A

V2B

V3A

V3B

V4A

V4B

SWITCHED

CAP ADC

SERIAL

INTERFACE

16

DATA

RESISTIVE

NETWORK

RESISTIVE

NETWORK

RESISTIVE

NETWORK

RESISTIVE

NETWORK

CLOCK

FEATURES

Fast 16-Bit ADC with 200 kSPS Throughput

Four Single-Ended Analog Input Channels

Single +5 V Supply Operation

Input Ranges: 0 V to +4 V, 0 V to +5 V and

10 V

120 mW Max Power Dissipation

Power-Down Mode 50

W

Choice of External or Internal 2.5 V Reference

On-Chip Clock

Power-Down Mode

GENERAL DESCRIPTION

The AD974 is a four-channel, data acquisition system with a

serial interface. The part contains an input multiplexer, a high-

speed 16-bit sampling ADC and a +2.5 V reference. All of this

operates from a single +5 V power supply that also has a power-

down mode. The part will accommodate 0 V to +4 V, 0 V to

+5 V or

±10 V analog input ranges.

The interface is designed for an efficient transfer of data while

requiring a low number of interconnects.

The AD974 is comprehensively tested for ac parameters such as

SNR and THD, as well as the more traditional parameters of

offset, gain and linearity.

The AD974 is fabricated on Analog Devices’ BiCMOS process,

which has high performance bipolar devices along with CMOS

transistors.

The AD974 is available in 28-lead DIP, SOIC and SSOP

packages.

PRODUCT HIGHLIGHTS

1. The AD974 is a complete data acquisition system combining

a four-channel multiplexer, a 16-bit sampling ADC and a

+2.5 V reference on a single chip.

2. The part operates from a single +5 V supply and also has a

power-down feature.

3. Interfacing to the AD974 is simple with a low number of

interconnect signals.

4. The AD974 is comprehensively specified for ac parameters

such as SNR and THD, as well as dc parameters such as

linearity and offset and gain errors.