Op-amp Spice macro-models article from Intersil
So anyway, Spice does not necessarily lie like Bob Pease says, but I guarantee you that if you give it poor models it will give you the wrong answer. This is the big hassle with op amp models. Some of them, like the old National Semi Comlinear models (pdf) published by Mike Steffes before he left for Burr Brown and now Intersil were essentially transistor-level models. An IC designer could infer the design of the part from them. Mike told me that he knew that, but it was just so important to give an accurate model that he felt he had to release those great models. If someone wanted to copy the circuits, well, they had a lot more work to do-anyone can de-cap an op amp and reverse engineer it in a day. That still does not give you the process or the testing regime or the design secrets and tricks.
That is why this Intersil article is so important. Anything that helps you make good models is important in a world where kid engineers trust a computer rather than a breadboard. The article give some history of op amp models and that will tip you off as to what you can expect from a simulation. If the model you use does not model for 1/f noise, and most vendor models do not, you cannot get a meaningful simulation of low-frequency noise performance of the circuit. If the model does include flat-band noise and you are designing and ac-coupled video circuit, well that is fine for your needs. I have yet to see a Spice op-amp model that accurately tells you what happens if you bang the output into the rails and saturate the transistors. I will ask Mike Steffes if his old Comlinear models would do that, and leave a comment.