Performance Optimization of OTA Using PSO Guided by Inversion Coefficient Theory

The paper deals with establishing a design procedure for a two stage CMOS operational transconductance amplifier (OTA). An automated technique is introduced that uses the widths and lengths of transistors and bias current in the circuit as variables to achieve desired specifications. Inversion Coefficient (IC) theory is used along with Particle Swarm Optimization (PSO) Algorithm to achieve optimum performance based on target characteristics like Gain Bandwidth Product (GBP), Gain, Phase Margin etc. The method can be easily extended to other analog circuits and parameters for design automation. The results showed a significant improvement in characteristics of the circuit as compared to the standard design procedure. Mentor Graphics EDA tool has been employed for running the simulations. TSMC018 library file is utilized which uses 180nm/1.8V CMOS technology parameters.On average, the gain of the test circuit is increased by 8.2%, the phase margin is improved by 39% and the GBP is observed to be four times the standard design procedure.