A low-voltage CMOS class-AB operational amplifier

This paper presents a CMOS low-voltage operational amplifier (opamp), which uses a minimum selector circuit to control the class AB operation of the output stage. The opamp basic characteristics are analyzed and simulated using the SMASH 4.0 simulator with the ACM model of the MOSFET. The supply voltage is 1.5 V and the total quiescent current is 4 /spl mu/A for a unity-gain frequency of 1 MHz. The class AB opamp was designed to operate in a sample-hold of the switched-MOSFET technique (SM), supplying a load with RC characteristic.