Research And Improvement Of High Gain And High Speed Operational Amplifier

Operational amplifier (op amp) circuit is one of the most important module in the analog circuit, and it is the most important basic unit in the linear circuit. Op amp is widely used in the power amplifier, timer, regulator and high sensitive measuring circuits.Many analog and mixed signal systems have performance that is limited by the settling behavior of op amps. These include switched capacitor filters, algorithmic A/D converters, sigma-delta converters, sample and hold circuits, and pipelined A/D converters. In these circuits the settling behavior of the op amp determines the accuracy and the speed. So, high gain and high speed are two of the most important characteristics of op amps.In this thesis, analysed and designed the architecture of the new type CMOS high gain high speed operational amplifier. Based on comparing the conventional approaches to achieving low frequency gain boosting, the designed amplifier in this thesis used the positive feedback gain-enhancement techniques. And open-loop pole bounds for positive feedback operational amplifiers are derived. It provides circuit designers with stability guidelines for positive feedback amplifier design. In order to have the better settling performance, the designed amplifier used the techniques of load-compensation and dynamic biasing. This amplifier is used the 0.6um BiCMOS process. When the power supply is 3.3V, the amplifier simulation results indicated that its static power consumes only 0.01mW, achieves about 70dB dc open gain. And the settling time is only 100ns, the Positive / negative slew rate is about 20.5 V/μS and 43V/μS. All of pre-defined specifications are satisfied with the simulation results.