Structural macromodeling of analog circuits through model decoupling and transformation

This paper presents a systematic methodology for developing structural macromodels expressing the linear and weakly nonlinear performance of analog circuits. The models are in the frequency domain. The methodology includes two steps. First, building-block behavioral (BBB) concept is used to describe the basic building blocks of a circuit, and a decoupling technique is used to generate uncoupled BBB structural circuit models. Then, a nonlinear system is represented as a system with nonlinear inputs and linearly coupled blocks, and the linear couplings are removed. Experiments are offered for single-stage OpAmp, three-stage OpAmp, and operational transconductor amplifier (OTA) circuits. The produced models are tunable for the required accuracy, offer insight into the circuit operation, and offer simulation time speedup as compared to SPICE simulation.