JM38510-12501BGA Datasheet, PDF (1/21 Pages) Texas Instruments – LF198JAN Monolithic Sample-and-Hold Circuits

LF198JAN
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SNOSAJ2A – FEBRUARY 2005 – REVISED MARCH 2013
LF198JAN Monolithic Sample-and-Hold Circuits
Check for Samples: LF198JAN
FEATURES
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•2 Operates from ±5V to ±18V Supplies
• Less Than 10 μs Acquisition Time
• TTL, PMOS, CMOS Compatible Logic Input
• 0.5 mV Typical Hold Step at C_h = 0.01 μF
• Low Input Offset
• 0.002% Gain Accuracy
• Low Output Noise in Hold Mode
• Input Characteristics Do Not Change During
Hold Mode
• High Supply Rejection Ratio in Sample or Hold
• Wide Bandwidth
• Space Qualified
Logic Inputs on the LF198 are Fully Differential
with Low Input Current, Allowing Direct
Connection to TTL, PMOS, and CMOS.
Differential Threshold is 1.4V. The LF198 will
Operate from ±5V to ±18V Supplies.
DESCRIPTION
The LF198 is a monolithic sample-and-hold circuit
which utilizes BI-FET technology to obtain ultra-high
dc accuracy with fast acquisition of signal and low
droop rate. Operating as a unity gain follower, dc gain
accuracy is 0.002% typical and acquisition time is as
low as 6 μs to 0.01%. A bipolar input stage is used to
achieve low offset voltage and wide bandwidth. Input
offset adjust is accomplished with a single pin, and
does not degrade input offset drift. The wide
bandwidth allows the LF198 to be included inside the
feedback loop of 1 MHz op amps without having
stability problems. Input impedance of 10¹⁰Ω allows
high source impedances to be used without
degrading accuracy.
P-channel junction FET's are combined with bipolar
devices in the output amplifier to give droop rates as
low as 5 mV/min with a 1 μF hold capacitor. The
JFET's have much lower noise than MOS devices
used in previous designs and do not exhibit high
temperature instabilities. The overall design ensures
no feed-through from input to output in the hold
mode, even for input signals equal to the supply
voltages.
Connection Diagrams
Figure 1. TO-99 Package
See Package Number LMC
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2
PRODUCTION DATA information is current as of publication date.
Products conform to specifications per the terms of the Texas
Instruments standard warranty. Production processing does not
necessarily include testing of all parameters.
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