Characterization of Normal Propagation Delay for Delay Degradation Model (DDM)

In previous papers we have presented a very accurate model that handles the generation and propagation of glitches, which makes an important headway in logic timing simulation. This model is called Delay Degradation Model (DDM). Characterizing DDM completely also implies the characterization of the normal propagation delay. In this paper, we propose a simple heuristic model that includes its dependence on the output load and the input transition time. We have tested this model and found a mean deviation lower than 4%. Also, we present a characterization process for this model that is fully integrated into AUTODDM without affecting the total simulation time needed to characterize a standard cell.