Design And Research Of High Speed Operational Amplifier Based On Current Drive Module

The field of integrated circuits has been in a stage of rapid development since the first integrated circuit came out in 1958.Among them,analog integrated circuits are an important branch of integrated circuits,and as the most important basic unit of analog integrated circuits,operational amplifiers have begun to develop in a functional direction with the expansion of application scenarios in different fields and the limitation of the octagonal rule.Operational amplifiers are mainly divided into generalpurpose operational amplifiers,low-noise operational amplifiers and high-speed operational amplifiers,etc.The requirements for low noise and high slew rate of functional operational amplifiers are also increasing with the upgrading of the consumer electronics market,however,the current operational amplifiers are difficult to meet market needs.The study of low-noise operational amplifiers and high-speed operational amplifiers therefore has a broad prospect and far-reaching research significance.This dissertation focuses on the design of operational amplifiers,the main contents are as follows:A general-purpose rail-to-rail operational amplifier is designed based on the parallel connection of complementary differential pairs and the Class AB architecture;a design method to implement the rail-to-rail input terminal of the operational amplifier is proposed,also the architecture of constant gm transconductance by the constant current method and an architecture of Class AB to implement rail-to-rail output are designed.The performance of operational amplifiers is optimized according to various design indicators of operational amplifiers.After the design and simulation of generalpurpose operational amplifiers,the layout of general-purpose operational amplifiers is drawn and post-simulated according to the layout design specifications.Finally,a general-purpose rail-to-rail operational amplifier with a gain of 110 d B,a phase margin of 60°,a bandwidth of 1.29 MHz,a quiescent current of 62.3 μA and a power supply rejection ratio of 105 d B is obtained under typical conditions.The performance of the designed general-purpose operational amplifier is optimized,and a low-noise rail-to-rail operational amplifier is designed.The source and influence of circuit noise are calculated and analyzed;the general-purpose operational amplifier is improved,and a low-noise rail-to-rail operational amplifier with an equivalent input voltage noise density of only 15.35 n V/sqrt(Hz)at a frequency of 1k Hz is designed,it indicates a significant performance improvement compared with a general-purpose operational amplifier with an equivalent input voltage noise density of52 n V/sqrt(Hz).A high-speed operational amplifier is designed based on the current drive module.In order to solve the problem of low slew rate at the output terminal of the operational amplifier,a current drive module is designed to increase the slew rate,and the workflow of the current drive module is analyzed,which effectively improves the slew rate of the operational amplifier;also the current drive module is upgraded and updated,which ensures both the stability of the operational amplifier and great improvement of the slew rate.Finally,a closed-loop-3 d B bandwidth of 314 MHz and slew rate of 284 V/μs high-speed operational amplifier is designed.