SHA1144_15 Datasheet, PDF (1/6 Pages) Analog Devices – HIGH RESOLUTION 14 BIT SAMPLE AND HOLD AMPLIFIER

ANALOG
W DEVICES
HighResolutio1n4-Bit
SampleandHoldAmplifier
FEATURES
:t10V min Input/Output Range
50ns Aperture Delay
~ ⁰6p^.5~ⁿT^si^Am^pe^{ertureJitter -A}
",;.r/.h';' _-r
:to.001% Max Gain Linearity Error
Complete with Input Buffer
APPLICA TlONS
Track and Hold
Peak Measurement Systems
Data Acquisition Systems
Simultaneous Sample-and-Hold
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OB _{~~ GENERAL DESCRIPTION}
S _{The SHAl144 is a fast sample-hold amplifier module with ac}
O curacy and dynamic performance appropriate for applications
with fast 14-bit AID converters. In the "sample" mode, it acts
L _{as a fast amplifier, tracking the input signal. When switched to}
E ^{the "hold" mode, the output is held at a level corresponding}
to the input signal voltage at the instant of switching. The
TE _{droop rate in "hold" is appropriate to allow accurate conver-}
FEEDBACK CONNECTIONS
A block diagram of the SHA1144 is shown in Figure 1. The in-
put section acts as a voltage-to-current converter, providing the
current needed to charge the "hold" capacitor. The output
amplifier isolates the "hold" capacitor and provides low out-
put impedance for driving the load. Since feedback is not hard-
wired in the module, both inverting and noninverting input
terminals are available, and the SHA1144 can be connected as
sion by 14-bit AID converters having conversion times of up
a follower with unity gain or potentiometric gain, as well as
to 150ps.
inverter or even a differential amplifier. Since the unity gain
DYNAMIC PERFORMANCE
The SHA1144 was designed to be compatible with fast 14-bit
AID converters such as the Analog Devices' ADCl130 and
ADC1131 series, which convert 14 bits in 25/1s and 12/1s, re-
spectively. Maximum acquisition time of 8ps for the SHA1144
follower mode will be the most frequent application, perform-
ance data listed in the specification table is based on this oper-
ating mode.
-15V
ANALOG
GROUND
+15V
permits high sampling rates for 14-bit conversions. The
SHAl144 is guaranteed to have a maximum gain nonlinearity
of :to.OOl % of full scale to insure 1/2LSB accuracy in 14-bit
systems. When in the "hold" mode, the droop rate is 1pV/ps,
so the SHA1144 will hold an input signal to :to.OO3% of full
scale (20V pop) for over 600ps.
PRINCIPLE OF OPERATION
The SHAl144 consists basically of two high speed operational
+INPUT
-INPUT
MODE
CONTROL
DIGITAL
GROUND
+ VOLTAGE
TO CURRENT
CONVERTER
1.5mA/V
HOLD CAPACITOR
OUTPUT
amplifiers, a storage capacitor, and a digitally controlled
switch. It differs from typical sample-and-hold modules in one
Figure 1. Block Diagram - SHA 1144
important respect; application versatility. The user completes
the SHAl144 feedback circuit external to the module. There-
fore, the module may be used in inverting or noninverting con-
figurations and can easily be arranged to provide circuit gain of
more than unity to simplify signal conditioning in a subsystem.
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 implica-
tion or otherwise under any patent or patent rights of Analog Devices.
P.O. Box 280; Norwood, Massachusetts 02062 U.S.A.
Telex: 924491
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