Modeling the effects of nonlinear materials in ceramic chip capacitors for use in digital and analog applications

This paper describes a physics-based numerical approach to building circuit models for electronic components that are made of nonlinear dielectrics. The resulting models are intended for use in time-domain circuit simulators to assess the effects of material nonlinearity on the electrical performance of such components as discrete de-coupling and filter capacitors that are used in digital and analog circuits. A 3-D electrostatic field solver is modified to take into account the nonlinear field dependence of the dielectric material and is employed to calculate the Q-V curve for any capacitive structure. Subsequently, a time integration method (similar to that used in SPICE) is utilized to devise an appropriate time-stepping algorithm for the current-charge relationship of a nonlinear capacitor that can be used to simulate its time-domain electrical characteristics. Sample results are provided to illustrate the methodology and the effects of the material nonlinearity on the performance of the capacitor