ftd: an exact frequency to time domain conversion for reduced order RLC interconnect models

Recursive convolution provides an exact solution for interfacing reduced-order frequency domain representations with discrete time domain models of piecewise linear voltage waveforms. The state-space method is more efficient, but not exact, and can sometimes produce large time domain errors. This paper presents a new algorithm, ftd (frequency to time domain), for incorporating linear frequency domain macro-models into time domain simulators. ftd provides accuracy equivalent to recursive convolution with efficiency that is superior to the state-space methods.