设计了一种宽带轨对轨运算放大器,此运算放大器在3.3 V单电源下供电,采用电流镜和尾电流开关控制来实现输入级总跨导的恒定.为了能够处理宽的电平范围和得到足够的放大倍数,采用用折叠式共源共栅结构作为前级放大.输出级采用AB类控制的轨对轨输出.频率补偿采用了级联密勒补偿的方法.基于TSMC 2.5μm CMOS工艺,电路采用HSpice仿真,该运放可达到轨对轨的输入/输出电压范围.%A wide-band rail-to-rail operational amplifier working with single power supply of 3. 3 V is designed. Current mirrors and tail current swithes are used to keep the transconductance of the input stage constant. In order to get enough gain and to deal with wider level range, the folded-cascode structure is adopted as the preamplifier. A class AB controJ is used in the outpur stage. The operational amplifier is compensated with the cascoded Miller frequency compensation technique. Based on the TSMC 2. 5 μm CMOS process, the circuit is simulated by HSpice. It can achieve rail-to-rail of signal input and output range.
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