Analog and mixed signal design: The level of simulation required for a first pass success.

What does the level of simulation have to be to predict the level of success of an IC? What does "level" imply? In the context of simulation of an IC, level implies how much of the IC was included in, perhaps a circuit simulation in a "SPICE-like" simulator. The reason this is so important is that in many cases it is not possible to simulate a full chip, specially if the chip contains mixed signal elements or large and small time constants, etc. Therefore the level of simulation for first pass success should be 100%. i.e the full chip was simulated under operating conditions that are a 100% identical to actual. It is of course not really possible to do this. It usually takes a combination of CAD tools to do this starting from MATLAB-SIMULINK, through circuit simulation and perhaps IBIS type modeling and simulation. In a few cases even more extensive simulation may be performed using Thermal Simulators. So the question remains:what is the level of simulation required for a high degree of confidence in the success of the chip? The answer must surely be that when all the CAD~tools have been used to their ultimate capacity, add a large measure of engineering judgment. This is the only way currently known! Please visit Signal Processing Group Inc.'s website at http://www.signalpro.biz for more technical papers and information.