Current Based Delay Models: A Must For Nanometer Timing

In order to accurately account for nanometer effects during timing analysis, traditional cell models must be replaced. The assumption of linear input voltages and lumped output load are no longer valid [1]. The existing cell delay models do not match well with the advanced interconnect delay models. Interconnect models consume linear voltage waveforms produced by these cell models and produce voltage waveforms for consumption by downstream cell models. Further, the arbitrary waveforms produced by these interconnect models are linearized for consumption by cell models. Current based delay models circumvent this problem and provide a cell delay model which can both produce and consume nonlinear current/voltage waveforms.