Design and optimisation of a two-stage amplifier based on a differential input stage and a common-source amplifier

Abstract. Since the emergence of integrated circuits, through the circuit structure, the production process of continuous iterative updating, so that its used in various types of electronic equipment more and more widely. Currently, operational amplifier circuits play an extremely important role in signal processing and communication systems. Amplifiers have different characteristics depending on the needs of different electronic devices. This thesis addresses the optimisation and design of the characteristics of the two-stages amplifier. Firstly, several classical amplifier structures are analysed. Select the appropriate structure and combine it into a two-stages amplifier. Simulation is carried out on cadence software and later the simulation results are analysed before parameter optimisation. On this basis, a two-stages amplifier based on a PMOS differential input stage with a common-source amplifier has been designed. It also improves the amplifier's gain, frequency range, gain bandwidth, and other performance metrics. Using PMOS self-bias circuit to improve power supply stability. Finally, based on the development hotspots of integrated circuits, the possibility of circuit optimization was analyzed. Discussions were conducted on negative feedback circuits, phase compensation methods, and other aspects.