一款低电压高精度CMOS运算放大器设计

Design of a low voltage high precision CMOS operational amplifier

设计了一种采用0.6um CMOS工艺的低电压高精度的运算放大器电路。在设计中输入级采用两对跨导器件rail-to-rail的电路结构,从而实现输入级的跨导在整个共模输入范围内保持恒定。输出级采用AB类rail-to-rail推挽结构,达到高驱动能力和低谐波失真的目的。此运放可提供1.5V电压降,采用适当的输出负载,闭环电压增益,单位增益带宽和相位裕度分别达到了80dB,832kHz和64°。

A low voltage high precision CMOS op- amp using 0.6urn CMOS process is described. We adopts two pairs of transconductors as rail - to- rail input stage to keep constant transconductance in the whole common mode input range. It also applies rail - to- rail push - pull symmetric class - AB output stage, achieve high drive capability and low harmonic distortion. The op - amp may provide 1.5V.voltage and proper load is adopted, achieve 80dB open- lcop gain, 832kHz unity- gain frequency and 64＊phase margin.