Only two decades ago most electronic circuits were designed with a slide-rule, and the designs were verified using breadboard techniques. Simulation tools were a research curiosity and in general were mistrusted by most designers and test engineers. In those days the programs were not user friendly, models were inadequate, and the algorithms were not very robust. The demand for simulation tools has been driven by the increasing complexity of integrated circuits and systems, and it has been aided by the rapid decrease in the cost of com puting that has occurred over the past several decades. Today a wide range of tools exist for analYSiS, deSign, and verification, and expert systems and synthesis tools are rapidly emerging. In this book only one aspect of the analysis and design process is examined. but it is a very important aspect that has received much attention over the years. It is the problem of accurate circuit and timing simulation.

This report deals with the development of a fast and accurate simulation tool for very-large-scale integrated (VLSI) circuits consisting of metal-oxide-semiconductor (MOS) transistors. Such tools are called switch-level timing simulators and they provide adequate information on the performance of the circuits with a reasonable expenditure of computation time even for very large circuits. The algorithms presented in this thesis can handle only n-channel MOS(NMOS) circuits, but are easily extendible to handle complementary MOS(CMOS) circuits as well. The algorithms presented in this report have been implemented in a computer program called MOSTIM. In all the circuits simulated thus far, MOSTIM provides timing information with an accuracy of within 10% of that provided by SPICE2, at approximately two orders of magnitude faster in simulation speed. (Author).