An optimized methodology to design CMOS operational amplifier

In this paper we present a method to optimize the design of CMOS operational amplifier. The purpose of this work is to give an optimal transistor sizing methodology in order to reach the op-amp desired characteristics. This is achieved by mean of simple calculations and accessible mathematic software. The idea consists of a mathematical formulation based on level 1 SPICE MOS model. Then, an objective function is defined according to the performances required. By mean of Maple software, we determine the optimal op-amp parameters. The proposed method is presented and applied to the design of standard CMOS op-amp using CMOS 0.35μm process. Simulations using PSPICE are presented and compared to theoretical calculations show the efficiency of our method.