200 μW CMOS class AB unity-gain buffers with accurate quiescent current control

Abstract

A new family of CMOS two-stage unity-gain buffers is presented, based on introducing Quasi-Floating Gate (QFG) techniques to achieve class AB operation. The resulting buffers feature simplicity, low supply voltage requirements, and low quiescent currents which are accurately set regardless of process, temperature, or supply variations. Measurement results for a 0.5 μm CMOS implementation of three class AB buffers powered at ±1.65 V show maximum output currents ranging from 64 to 92 times the quiescent currents and static power consumption below 200 μW.