一种低压高性能的Rail-to-Rail运算放大器  

A Rail-to-Rail Operational Amplifier with Low Voltage and High Performance

作　　者：王丹[1] 姜宇[2] 郭桂良[2] 吕英杰[1] 

机构地区：[1]南开大学电子信息与光学工程学院,天津300071 [2]中国科学院微电子研究所,北京100029

出　　处：《微电子学与计算机》2017年第2期68-72,共5页Microelectronics & Computer

摘　　要：采用TSMC 0.18μm CMOS工艺,设计实现了一种低压恒跨导、高性能的Rail-to-Rail运算放大器.输入级采用NMOS和PMOS并联的互补差分对结构,使共模输入电压范围达到Rail-to-Rail,并通过改进的开关电流结构使输入级的有效跨导在共模输入范围内保持恒定.输出级采用反馈式AB类结构,以达到输出电压的全摆幅,同时通过米勒补偿控制零极点来保证放大器工作的稳定性.整个电路在1V的单电源电压,20pF负载电容的工作条件下工作,Spectre仿真结果显示,直流开环增益为127dB,单位增益带宽为6.4 MHz,相位裕度67.58°,总谐波失真为-107dB.A rail-to-rail operational amplifier with low voltage constant transconductance and high performance is introduced with TSMC 0.18μm CMOS process. The input stage uses NMOS and PMOS complementary differential pairs to make the common-mode input voltage rail-to-rail. Meanwhile the input stage uses current switches with constant common-mode output current to keep the effective transconductance constant over the whole input range. A class-AB output stage with folded mesh feedback is used to achieve the rail-to-rail output range. And miller compensation is adopted to guarantee the stability of the operational amplifier by controlling the zero and pole. The whole circuit is simulated in Cadence Spectre with a single 1 V supply. The simulation results show that the dc open- loop gain of the op-amp is more than 127 dB, and the unity-gain frequency is 6.4 MHz with phase margin of 67.58° while driving 20 pF. The total harmonic distortion of a unity-gain connected amplifier is --107 dB.

关 键 词：恒跨导 RAIL-TO-RAIL 运算放大器 AB类 

分 类 号：TN432[电子电信—微电子学与固体电子学]