Two-stage operational amplifier with Class A and B output stage

Since the 20th century, with the development of portable electronic devices, the status of analog integrated circuits has gradually improved. Correspondingly, the design of the operational amplifier is very crucial. Therefore, the optimized design of operational amplifiers is still a concern, especially in terms of the reduction of chip size, the increase of work efficiency and the reduction of power consumption. This paper uses the Class A and B output stage as the output of the operational amplifier, and designs a more practical two-stage operational amplifier consisting of an input-stage amplifier circuit, a two-stage amplifier circuit and an output circuit. The overall output voltage swing is 0.8V-2.2V, and the unity gain bandwidth is 27.54MHz with a moderate DC bias of 1.4V.