A low-voltage BiMOS op amp

Describes the development of a threshold implanted BiMOS amplifier IC optimized for 2-5 V operation at a supply current of 300 /spl mu/A. A nonlinear operational transconductance amplifier (OTA) buffer having on-chip feedback provides a low-impedance rail-to-rail output, and a bulk-modulated PMOS input pair extends the common-mode range. Protective-network bootstrapping makes possible subpicoampere input-bias currents below 85/spl deg/C, and improved offset stability is achieved by the choice of threshold-level stage currents. Amplifier design is straightforward and readily applied from `micropower' to `broad-band' operating ranges. The combination of these features has produced a unique high-performance integrated circuit.