a
FEATURES
100 kHz Throughput Rate
Fast 12-Bit Sampling ADC with 8 s Conversion Time
8-Pin Mini-DIP and SOIC
Single +2.7 V to +5.5 V Supply Operation
High Speed, Easy-to-Use, Serial Interface
On-Chip Track/Hold Amplifier
Analog Input Range is 0 V to Supply
High Input Impedance
Low Power: 9 mW typ
2.7 V to 5.5 V, 12-Bit, 8 s
ADC in 8-Pin SO/DIP
AD7896*
FUNCTIONAL BLOCK DIAGRAM
V
DD
AD7896
TRACK/HOLD
V
IN
12-BIT
ADC
CONVST
CLOCK
OUTPUT
REGISTER
AGND
DGND
BUSY
SCLK
SDATA
GENERAL DESCRIPTION
PRODUCT HIGHLIGHTS
The AD7896 is a fast, 12-bit ADC which operates from a single
+2.7 V to 5.5 V supply and is housed in a small 8-pin mini-DIP
and 8-pin SOIC. The part contains an 8
µs
successive approxi-
mation A/D converter, an on-chip track/hold amplifier, an on-
chip clock and a high speed serial interface.
Output data from the AD7896 is provided via a high speed,
serial interface port. This two-wire serial interface has a serial
clock input and a serial data output with the external serial clock
accessing the serial data from the part.
In addition to the traditional dc accuracy specifications such as
linearity, full-scale and offset errors, the AD7896 is also speci-
fied for dynamic performance parameters including harmonic
distortion and signal-to-noise ratio.
The part accepts an analog input range of 0 V to V
DD
and oper-
ates from a single +2.7 V to +5.5 V supply consuming only
9 mW typical. The V
DD
input is also used as the reference for
the part so that no external reference is required.
The AD7896 features a high sampling rate mode and, for low
power applications, a proprietary automatic power down mode
where the part automatically goes into power down once con-
version is complete and “wakes up” before the next conversion
cycle.
The part is available in a small, 8-pin, 0.3'' wide, plastic or her-
metic dual-in-line package (mini-DIP) and in an 8-pin, small
outline IC (SOIC).
*Patent
pending.
1. Complete, 12-bit ADC in 8-Pin Package
The AD7896 contains an 8
µs
ADC, a track/hold amplifier,
control logic and a high speed serial interface, all in an 8-pin
DIP. The V
DD
input is used as the reference for the part so
no external reference is needed. This offers considerable
space saving over alternative solutions.
2. Low Power, Single Supply Operation
The AD7896 operates from a single +2.7 V to 5.5 V supply
and consumes only 9 mW typical. The automatic power
down mode, where the part goes into power down once con-
version is complete and “wakes up” before the next conver-
sion cycle, makes the AD7896 ideal for battery powered or
portable applications.
3. High Speed Serial Interface
The part provides high speed serial data and serial clock lines
allowing for an easy, two-wire serial interface arrangement.
REV. B
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.
© Analog Devices, Inc., 1996
One Technology Way, P.O. Box 9106, Norwood, MA 02062-9106, U.S.A.
Tel: 617/329-4700
Fax: 617/326-8703
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