Ramp input response of RC tree networks

Closed form expressions are presented to accurately describe the delay characteristics of RC tree networks. The Penfield-Rubinstein-Horowitz approach to estimating the step function response of RC trees has been extended to consider ramp inputs. This improves timing accuracy by considering the shape of the input waveform driving each individual interconnect tree while maintaining computational simplicity for use in the automated timing analysis of complex VLSI circuits.