LF398N/NOPB

The LF398N/NOPB is a monolithic Sample-and-Hold Circuit uses BI-FET technology to obtain ultrahigh DC accuracy with fast acquisition of signal and low droop rate. Operating as unity-gain follower, DC gain accuracy is 0.002% typical and acquisition time is as low as 6µs 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-N to be included inside the feedback loop of 1MHz operational amplifiers without having stability problems. Input impedance of 10¹⁰R allows high-source impedances to be used without degrading accuracy. P-channel junction FETs are combined with bipolar devices in the output amplifier to give droop rates as low as 5mV/minute with a 1µF hold capacitor. The JFETs have much lower noise than MOS devices used in previous designs and do not exhibit high temperature instabilities.

• Low input offset
• Low output noise in hold mode
• Input characteristics do not change during hold mode
• High supply rejection ratio in sample or hold
• Wide bandwidth
• Logic input compatible with TTL, PMOS and CMOS
• 0.5mV Typical hold step at 0.01µF
• 0.002% Gain accuracy
• 500mW Power dissipation
• ±15V Supply voltage