Streamlined Circuit Device Model Development with fREEDA® ãnd ADOL-C

Abstract

Time-marching simulation of electronic circuits using the U.C. Berkeley program Spice and variants has been a standard practice for electronics engineers since the mid-1970s. Unfortunately, the development cycle of Spice models may be lengthy because device model equations and their derivatives must be coded manually. Also, many files in the source tree must be modified to define a new model. fREEDA®, www.freeda.org, an object-oriented circuit simulator under development at several universities, overcomes many limitations of the conventional electronic model development paradigm. A key to this implementation is the ADOL-C package, which is used to automatically evaluate the derivatives of the device model equations. Resulting models are more compact, and the development time is shorter. The development history of selected Spice models and their fREEDA® counterparts are presented to illustrate the advantages of this approach.