Determining the dominant nonlinear contributions in a multistage op-amp in a feedback configuration

In this paper a simulation based method is proposed to determine the position of the dominant nonlinear contribution in the schematic of multistage op-amp operated in a feedback configuration. The key idea is to combine the Best Linear Approximation (BLA) and a classical noise analysis to determine the dominant source of nonlinear contributions. This results in a powerful yet simple design tool which does not require special analyses or custom models. As an example, the method is applied to a folded-cascode op-amp.