Gain-Based Double Feedforward Compensation for Multi-Stage Amplifiers

Abstract

A gain-based double feedforward compensation (GBDFC) for multi-stage amplifiers is proposed, which could be used in multi-stage OTA design. The proposed compensation technique provides two left-plane zeros to counteract with the first and second non-dominant poles of the OTA without reducing the dominant pole obviously. Meanwhile, a high slew-rate is presented in the condition of large step input signal. A three-stage Opamp prototype with the proposed technique is realized in a 0.18 yitm CMOS process. The post simulation results show that it provides a unity-gain bandwidth (GBW) of 103 MHz and phase margin (PM) of 70° with power consumption of 0.328 mW and small compensation capacitors, implying a better FOM compare with the state-of-the-art.