A low voltage class AB CMOS amplifier

Abstract

A new class AB CMOS operational amplifier (opamp) principle is presented. It is based on a novel self-biasing input transistor technique. The operational transconductance amplifier (OTA) utilizing this principle exhibits similar small signal characteristics of conventional OTAs. It has, however, a superior large signal behavior and its settling time is not slew-rate limited. It also overcomes the difficulties of unconditional stability inherent in some class AB opamps. It is particularly suited for low voltage operation. Due to the generality of the proposed technique, the principle can be applied to many other circuit topologies.