A design procedure for three-stage operational amplifier using indirect compensation technique

Abstract

This paper presents a design procedure for the operational amplifier (Opamp) using indirect compensation technique. It provides a step-by-step guideline for designing an operational amplifier. Then a three-stage Opamp has been designed as an example. This Opamp achieves an open loop gain above 90dB, 70MHz gain-bandwidth product (GBW) and 68° phase margin (PM) at large capacitive load CL of 30pF in a 0.18μm CMOS technology. The supply voltage Opamp is 1.8V with the power dissipation of 826.45μW.