Improving Analytical Delay Modeling for CMOS Inverters

Analytical methods for gate delay estimation are very useful to speedup timing analysis of digital integrated circuits. This work presents a novel approach to analytically estimate the CMOS inverter delay. The proposed method considers the influence of input slope, output load and I/O coupling capacitance, as well as relevant effects such as channel length modulation and drain induced barrier lowering. Experimental results are on good agreement with HSPICE simulations, showing significant accuracy improvement compared to published related work. The delay model error has an average value of 3%, and the worst case error is smaller than 10%.