OTA Performance Space Modeling for System-Level Optimization of SC-circuits

This paper is about high-level modeling of analog circuits based on its complete feasible performance space. The behavioral model is a multi-dimensional description of all enclosing surfaces of this space, approximated by a set of boundary points. An exploration method, applying the Normal Boundary Intersection with a novel constraint rotation method, is shown to calculate these boundary points. The solutions are found by transistor level spice simulations, which leads to a highly accurate approximated model. A fully-differential transconductance amplifier with folded cascode and class-AB output stage is taken as example circuit, whose performance space model is calculated by the deterministic exploration scheme. The resulting model is used to perform an efficient system level optimization towards accuracy of a switched capacitor circuit.