Computational Delay Models to Estimate the Delay of Floating Cubes in CMOS Circuits

Abstract

The verification of the timing requirements of large VLSI circuits is generally performed by using simulation or timing analysis on each combinational block of the circuit. A key factor in timing analysis is the election of the delay model type. Pin-to-pin delay models are usually employed, but their application is limited in timing analysis when dealing with floating mode or complex gates. This paper does not introduce a delay model but a delay model type called Transistor Path Delay Model (TPDM). This new type of delay model is specially useful for timing analysis in floating mode, since it is not required to know the whole input sequence to apply it, and can manage complex CMOS gates. An algorithm to get upper bounds on the stabilization time of each gate output using TPDM is also introduced.