Simple and Accurate Model for the Propagation Delay in MCML Gates

In this article, we develop a simple and accurate model for evaluating the propagation delay in MOS Current-Mode Logic (MCML) gates. The model describes the behavior of MCML gates in a linear fashion despite the circuits themselves being non-linear. Indeed, we demonstrate that a linear model can be used, provided that, for each small-signal parameter, its average value calculated between the two different switching logic states is used. The proposed model is validated through simulations of MCML universal gates designed using modern nanometer processes. The model forecasts simulated values with an error lower than 4% and 20% in 65-nm standard CMOS and 28-nm Fully-Depleted Silicon-On-Insulator (FD-SOI), respectively.