资 源 简 介
The LF198/LF298/LF398 are monolithic sample-and-holdcircuits which uTIlize BI-FET technology to obtain ultra-highdc accuracy with fast acquisiTIon of signal and low drooprate. OperaTIng as a unity gain follower, dc gain accuracy is0.002% typical and acquisiTIon time is as low as 6 μs to0.01%. A bipolar input stage is used to achieve low offsetvoltage and wide bandwidth. Input offset adjust is accomplishedwith a single pin, and does not degrade input offsetdrift. The wide bandwidth allows the LF198 to be included insidethe feedback loop of 1 MHz op amps without having stabilityproblems. Input impedance of 1010W allows highsource impedances to be used without degrading accuracy.P-channel junction FET’s are combined with bipolar devicesin the output amplifier to give droop rates as low as 5 mV/minwith a 1 μF hold capacitor. The JFET’s have much lowernoise than MOS devices used in previous designs and donot exhibit high temperature instabilities. The overall designguarantees no feed-through from input to output in the holdmode, even for input signals equal to the supply voltages.
