Simulating delta-sigma analog-to-digital converters with the Op-Amp nonlinearity using the Newton´s method

This paper presents a system-level simulation technique for the delta-sigma analog-to-digital converters. The integrator in an analog delta-sigma modulator consists of an op amp and the large-signal model of an op amp is nonlinear. Therefore, the conventional linearized system-level simulation of the DSM using only the linear model is not sufficiently accurate. This work employs the Newton´s method in the proposed simulation technique to solve the problem encountered in the conventional simulations. The new technique is implemented using the Mat-lab/Simulink tool. The proposed method is verified by comparing the system-level simulation results with the Hspice circuit-level simulation results.