Research And Design Of High-gain Cmos Fully Differential Op Amp

While the electronic products, especial IC (integrated circuit), take mainpossession of the market and their performance are in high challenge. To solve thisproblem ,we had to take care in such aspect as circuit structure,material,technology.Here, we are devoted to the research of the circuit optimization.Operational amplifier is a full and basic part of most analog system andmixer-signal processing system, and it is critical in the design Good performanceoperational amplifier will enhance the properties of the system. Now, the researchfocus on the high speed signal processing and low power dissipation, which areappropriate domains we can make breakout.In this article, we first introduce the specifications of the CMOS operationalamplifier. These specification include open loop gain,output swing,slew rate,noise,which are the criterions of the amplifier .Then ,the architecture and function ofamplifiers are analyzed, mainly basic differential pair, folded-cascode and telescopicoperational amplifier .At the same time, we discuss the common mode feedbackcircuit and its property. Thus is the start point of our design work. And then,considering the high gain and low power dissipation, telescopic operational amplifieris implanted and the parameter is specifiable. The DC characteristic and ACcharacteristic and noise analysis are simulated. We get good results: 78dBopen-loop gain and 15mW power dissipation. It almost meets our expected goal.At the last, with the knowledge of usage of cadence and the design rules of layout,we draw the structure of the telescopic operational amplifier.