Practical modeling for circuit simulation

There is much more to modeling for circuit simulation than deriving a set of I(V), and perhaps Q(V), equations and extracting a SPICE.MODEL card. Unfortunately, some practical aspects of modeling are often overlooked. This paper details common-sense guidelines for modeling and highlights common modeling problems. Particular emphasis is given on understanding accuracy requirements and numerical requirements, on ensuring that compact models are asymptotically correct, and on highlighting the real goal of modeling for circuit simulation: getting complete models for allowable device layouts working in the CAD system on a designer's desk.