A High Gain, 808MHz GBW Four-Stage OTA in 65nm CMOS

Abstract

A four-stage operational transconductance amplifier (OTA) with a novel compensation structure combining multipath [Formula: see text]-[Formula: see text] compensation and no capacitor feed-forward compensation is proposed in this paper. Based on the small-signal model, stability analysis and design consideration are carried out to demonstrate the stability of the compensation technique. To verify the effectiveness of the compensation scheme, the proposed OTA which drives a 2 pF capacitance, is simulated in TSMC 65[Formula: see text]nm 1.2[Formula: see text]V CMOS process, achieving 808[Formula: see text]MHz gain-bandwidth, 119[Formula: see text]dB DC gain, 585[Formula: see text]V/[Formula: see text]s slew rate (SR) and 6 ns 1% settling time. The circuit is operated at the single supply voltage of 1.2[Formula: see text]V with power consumption of 2.17[Formula: see text]mW and the layout area is 0.011[Formula: see text]mm2.