부산대학교 도서관

Operational amplifiers, also known as op-amps, are most widely used in various real-time engineering applications such as mixed signal processing, analog circuit design, and etc. They have become fundamental components in various fields, such as electronics and telecommunications. These amplifiers are primarily designed to amplify small signals into various voltages. In this paper, we propose three op-amp circuits. The first is a three stage op-amp only with analog switches that performs two stage and three stage amplifications according to the select line of the switch. The second is a three stage op-amp with two extra CS amplifiers that performs two stage and three stage amplifications simultaneously. The third one is a modification of the telescopic op-amp, which produces two different gains according to the control value. All the conventional existing and proposed opamps are designed with 180nm CMOS technology using Cadence Virtuoso.