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FEATURES
Four Matched Sample-and-Hold Amplifiers
Independent Inputs, Outputs and Control Pins
500 ns Hold Mode Settling
1 s Maximum Acquisition Time to 0.01%
Low Droop Rate: 0.01 V/ s
Internal Hold Capacitors
75 ps Maximum Aperture Jitter
Low Power Dissipation: 430 mW
0.3" Skinny DIP Package
MIL-STD-883 Compliant Versions Available
Four-Channel
Sample-and-Hold Amplifier
AD684*
FUNCTIONAL BLOCK DIAGRAM
PRODUCT DESCRIPTION
PRODUCT HIGHLIGHTS
The AD684 is a monolithic quad sample-and-hold amplifier
(SHA). It features four complete sampling channels, each
controlled by an independent hold command. Each SHA is
complete with an internal hold capacitor. The high accuracy
SHA channels are self-contained and require no external
components or adjustments. The AD684 is manufactured on a
BiMOS process which provides a merger of high performance
bipolar circuitry and low power CMOS logic.
The AD684 is ideal for high performance, multichannel data
acquisition systems. Each SHA channel can acquire a signal in
less than 1
µs
and retain the held value with a droop rate of less
than 0.01
µV/µs.
Excellent linearity and ac performance make
the AD684 an ideal front end for high speed 12- and 14-bit
ADCs.
The AD684 has a self-correcting architecture that minimizes
hold mode errors and insures accuracy over temperature. Each
channel of the AD684 is capable of sourcing 5 mA and
incorporates output short circuit protection.
The AD684 is specified for three temperature ranges. The J
grade device is specified for operation from 0 to +70°C, the A
grade from –40°C to +85°C and the S grade from –55°C to
+125°C.
*Protected by U.S. Patent Number 4,962,325.
1. Fast acquisition time (1
µs)
and low aperture jitter (75 ps)
make the AD684 the best choice for multiple channel data
acquisition systems.
2. Monolithic construction insures excellent interchannel
matching in terms of timing and accuracy, as well as high
reliability.
3. Independent inputs, outputs and sample-and-hold controls
allow user flexibility in system architecture.
4. Low droop (0.01
µV/µs)
and internally compensated hold
mode error results in superior system accuracy.
5. The AD684’s fast settling time and low output impedance
make it ideal for driving high speed analog to digital
converters such as the AD578, AD674, AD7572 and the
AD7672.
6. The AD684 is available in versions compliant with MIL-
STD-883. Refer to the Analog Devices
Military Products
Databook
or current AD684/883B data sheet for detailed
specifications.
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: 617/329-4700
Fax: 617/326-8703
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