ABSTRACT
Analog circuit simulation usually means simulation of analog circuits or very detailed simulation of digital circuits. The most widely known and used circuit simulation program is SPICE (simulation program with integrated circuit emphasis) of which it is estimated that there are over 100,000 copies in use. SPICE was first written at the University of California at Berkeley in 1975, and was based on the combined work of many researchers over a number of years. Research in the area of circuit simulation continues at many universities and industrial sites. Commercial versions of SPICE or related programs are available on a wide variety of computing platforms, from small personal computers to large mainframes. A list of some commercial simulator vendors can be found in the Appendix. The focus of this chapter is the simulators and the theory behind them. Examples are also given to illustrate their use.
Computer-aided simulation is a powerful aid for the design or analysis of VLSI circuits. Here, the main emphasis will be on analog circuits; however, the same simulation techniques may be applied to digital circuits, which are composed of analog circuits. The main limitation will be the size of these circuits because the techniques presented here provide a very detailed analysis of the circuit in question and, therefore, would be too costly in terms of computer resources to analyze a large digital system. However, some of the techniques used to analyze digital systems (like iterated timing analysis or relaxation methods) are closely related to the methods used in SPICE.
