Active-feedback frequency compensation for low-power multi-stage amplifiers

Abstract

This paper describes a novel active-feedback frequency compensation (AFFC) technique for low-power multi-stage amplifiers. With a high-speed active feedback block, the proposed compensation technique significantly improves both the frequency and the transient responses of the amplifier. Implemented by a standard 0.8/spl mu/m CMOS process, a three-stage AFFC amplifier achieves 100dB gain, 4.5MHz gain-bandwidth product, 65/spl deg/ phase margin and 1.5V//spl mu/s slew rate with 0.4mW power consumption when driving a 100pF capacitive load.