Passive closed-form time-domain macromodels for on-chip distributed RC interconnects

This paper presents a closed-form passive time-domain macromodeling algorithm for multiport distributed RC interconnect networks. The method offers an efficient means to discretize RC distributed interconnects compared to the conventional lumped discretization while preserving the passivity of the macromodel. In the proposed method, coefficients describing the discrete time-domain macromodel are computed using closed-form matrix rational approximation of exponential matrices and can be computed a priori. The proposed model is suitable for inclusion in general purpose circuit simulators such as SPICE and overcomes the mixed frequency/time simulation difficulties encountered during transient analysis.