a
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
4-Channel, 16-Bit, 200 kSPS
Data Acquisition System
AD974
FUNCTIONAL BLOCK DIAGRAM
PWRD
BIP
VDIG
REF
CAP
REF
BUFF
V1A
V1B
V2A
V2B
V3A
V3B
RESISTIVE
NETWORK
VANA
2.5V
REFERENCE
AD974
EXT/INT
RESISTIVE
NETWORK
RESISTIVE
NETWORK
SWITCHED 16
CAP ADC
4 TO 1
MUX
+
LATCH
DATACLK
SERIAL
INTERFACE
CS
CLOCK
V4A
V4B
RESISTIVE
NETWORK
AGND1 AGND2
SYNC
EN
CONTROL LOGIC
&
CALIBRATION CIRCUITRY
GENERAL DESCRIPTION
The AD974 is a four-channel, data acquisition system with a
serial interface. The part contains an input multiplexer, a highspeed 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 powerdown mode. The part will accommodate 0 V to +4 V, 0 V to
+5 V or ± 10 V analog input ranges.
DATA
R/C
A0 A1 WR1 WR2
BUSY
DGND
PRODUCT HIGHLIGHTS
The interface is designed for an efficient transfer of data while
requiring a low number of interconnects.
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.
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.
2. The part operates from a single +5 V supply and also has a
power-down feature.
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.
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.
REV. A
Information furnished by Analog Devices is believed to be accurate and
reliable. However, no responsibility is assumed by Analog Devices for its
use, nor for any infringements of patents or other rights of third parties
which may result from its use. No license is granted by implication or
otherwise under any patent or patent rights of Analog Devices.
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
