Free class AB–AB Miller opamp with high current enhancement

Abstract

A two-stage (Miller) operational amplifier (opamp) with both class AB input and output stages is introduced. It has a well-controlled quiescent current and generates dynamic output currents of up to a factor 45 times larger than the quiescent current. It uses very compact circuitry with small static power consumption in order to achieve class AB–AB operation and can operate with a low supply voltage. Experimental results of a test chip fabricated using 0.18 μm CMOS technology and simulations in 130, 90, 65 and 45 nm verify the proposed circuit.