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.
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
V
DIG
V
ANA
EXT/INT
DATACLK
R/C
CS
SYNC
DGNDBUSYWR2WR1A1A0AGND2AGND1
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 610 V
120 mW Max Power Dissipation
Power-Down Mode 50 mW
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.