LF198QML-SP

ACTIVE

Monolithic Sample and Hold Circuit

Product details

Rating Space Operating temperature range (°C) -55 to 125
Rating Space Operating temperature range (°C) -55 to 125
CFP (NAC) 14 62.9285 mm² 9.91 x 6.35
  • 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 Ch = 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

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  • 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 Ch = 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

All trademarks are the property of their respective owners.

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 specifies no feed-through from input to output in the hold mode, even for input signals equal to the supply voltages.

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.

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 specifies no feed-through from input to output in the hold mode, even for input signals equal to the supply voltages.

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.

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Type Title Date
* Data sheet LF198QML Monolithic Sample-and-Hold Circuits datasheet (Rev. A) 20 Mar 2013
* SMD LF198QML-SP SMD 5962-87608 21 Jun 2016
Application brief DLA Approved Optimizations for QML Products (Rev. A) PDF | HTML 05 Jun 2024
Selection guide TI Space Products (Rev. J) 12 Feb 2024
More literature TI Engineering Evaluation Units vs. MIL-PRF-38535 QML Class V Processing (Rev. A) 31 Aug 2023
Application note Heavy Ion Orbital Environment Single-Event Effects Estimations (Rev. A) PDF | HTML 17 Nov 2022
Application note Single-Event Effects Confidence Interval Calculations (Rev. A) PDF | HTML 19 Oct 2022

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