A 50-fA junction-isolated operational amplifier

A monolithic op amp with 50-fA input current, 0.25-mV offset voltage, and 5- mu m V/ degrees C offset drift has been fabricated on a linear bipolar junction-isolated process. The low input current is achieved by using a pair of low-leakage four-terminal JFETs as input devices. Drift and offset voltage are adjusted by laser trimming on-chip thin-film resistors. The input JFET and the design of the amplifier are discussed.<
>