Simplified Symbolic Gain, CMRR and PSRR Analysis of Analog Amplifiers Using Simulated Annealing

Abstract

Modeling common-mode rejection ratio (CMRR) and power-supply rejection ratio (PSRR) is of utmost importance during the design of analog integrated circuits. Unfortunately, symbolic analysis suffers from the exponential growing of the complexity of expressions with the circuit size, symbolic simplification techniques should be utilized for the analysis of practical circuits. In this paper, we propose a methodology for the automatic simplified symbolic analysis of gain, CMRR and PSRR in analog amplifiers. We introduce a multi-objective simulated annealing for the simplification of derived symbolic expressions. The fitness function is to minimize the number of symbolic terms while satisfying the optimization constraints. In contrast to the classical criteria which simplify different polynomials separately, the main objective of the proposed criterion is to consider the correlation between different polynomials, during the simplification procedure. The method has been successfully coded in MATLAB and simulated over two analog amplifiers. Comparison of the numerical results extracted from the simplified symbolic expressions with HSPICE demonstrates the efficiency of the proposed methodology.