Research And Design Of CMOS Fully Differential Amplifier

Since integrated circuits were invented in the fifties of last century, integrated circuits have been developed with amazing speed throughout the past few decades. The theoretical basis for the circuit structure and the manufacturing process undergoes great changes, and now integrated circuits are in-depth applied in every aspect of people’s lives.During the process of development, the design of operational amplifier is changed from the original general type to custom-made type for different application environments. This paper first analyzed the main indicators of op-amp, and compared several classic operational amplifier structures. On the basis of traditional fully differential operational amplifier, designed a new CMOS differential operational amplifier to increases the open-loop DC gain, unit gain bandwidth and slew rate.Based on CSMC 0.5μm CMOS process model, the operational amplifier designed in the paper is simulated by the tools of Specture, in the Cadence software environment. In the normal environment, the operational amplifier has DC gain of 99.47 dB, unity-gain bandwidth of 204.2MHz, phase margin of 68°, slew rate of 221 V/μs, common mode reject ratio of 77.24 dB, power supply rejection ratio of 77.468. The landscape area is 13550μm2.