The Design Of Low-voltage And Low-consumption Cmos Operational Amplifiers

In the research of biology and space technology,integrated circuits must work in low voltage and low power.It is very important to adopting low voltage analog circuits to reduce the power consumption.Now,low-voltage and low-power analog circuit design techniques are becoming one of research hotspots.In the analog IC,one of the typical circuits is operational amplifier on which the whole system capability is depending.Therefore,the design of low-voltage and low-voltage operational amplifier is very necessary.The thesis based on the fundament of operational amplifier,combined with the domestic and abroad technologies of analogy low voltage and low power on which designed a 0.95 V low-voltage low-power and rail-to-rail CMOS operational amplifier. When designing the input stage,applying the NMOS tube and PMOS tube parallel supplementary differential input pair,and applying the proportional current mirror technology to achieve the constant transconductance of input stage.In the middle gain stage design,the current mirror load did not use the traditional standard cascade structure,but used the low voltage,wide-swing casecode structure which was suitable to work in low voltage.When designing output stage,in order to enhance the efficiency,it used the class AB push-pull amplifier as the output stage,the output voltage swing basically reached rail-to-rail.The thesis used the Miller compensate technology with a adjusting zero resistance to compensate the operational amplifier.The circuit design is realized in CSMC 0.35μm CMOS technology and HSPICE simulation results of CMOS indicate that it consumes only 2.375 mW,achieves the dc open gain of 70 dB,unity-gain frequency of 2.5 MHz,and the phase margin of 60°in 0.95 V power supply.All of pre-defined specifications are satisfied with the simulation results.