Simulation-equation-based methodology for design of CMOS amplifiers using Geometric Programming

Geometric programming (GP) has been employed in automatic design of analog integrated circuits. Its major advantage is the ability to find the globally optimum solution to a problem. It however, suffers from dependency on the accuracy of the initial equations and the parameters used in these equations. This, in circuit design, causes discrepancies between GP predictions and simulation results-especially in sub-micron devices-thus resulting in a non-globally optimum circuit design. In this paper, two major sources of this discrepancy are introduced and resolved by an iterative simulation-equation-based design methodology based on GP for operational amplifiers. In order to show the effectiveness of the methodology, it has been applied to two op-amp architectures.