Ultra-Wide Bandwidth Fully Differential CMOS Opamp with a Novel Bandwidth Extension Technique for SoC Active Filter Applications

Abstract

An ultra-wide bandwidth fully differential two-stage 65[Formula: see text]nm CMOS operational amplifier (Opamp) is presented, which uses a novel bandwidth extension technique called “pole duplication”. This technique is based on relocating the dominant pole with the same location with a non-dominant pole and adjusting 3-dB frequency and stability with a compensation network. Simulation results show that the proposed Opamp has 103[Formula: see text]MHz 3-dB bandwidth with a 2[Formula: see text]pF load capacitor. It consumes 9[Formula: see text]mA current from 1.2-V supply. Transition frequency of 2.4[Formula: see text]GHz and a gain of 29[Formula: see text]dB is accomplished. A 2[Formula: see text]pF load capacitance can be driven at a phase margin of [Formula: see text]. The suggested pole duplication technique is used to achieve higher 3-dB cut-off frequencies by adjusting the load capacitor. Fully differential two-stage Opamp is presented, which uses a novel bandwidth extension technique, is suitable for SoC active filter applications with 40[Formula: see text][Formula: see text]m layout area and ultra-wide 3-dB bandwidth.