The Designer's Guide® Community website is a place where analog, mixed-signal and RF circuit designers come to learn about simulation, modeling and design. There are a number of very practical papers on simulation and modeling on the Analysis, Modeling, and Theory pages. A collection of useful example models can be found on the Verilog-AMS page. Papers on design methodology can be found on the Design page. And finally, our most popular feature is the Forum, where designers gather to share information about the challenges they face. The Designer's Guide Community is built around the contributions of its members. Most chose to contribute through discussions on the Forum, but some go so far as to write and contribute either papers or models. So if you have some special knowledge you would like to share, or if some useful and well-written models, please consider submitting them.

@Art Scott Best links. One of the best resources that survives time. I used them more than 17 years ago