Benchmark Tests for MOSFET Compact Models

It has long been recognized that, apart from computational efficiency and accuracy of fitting experimental data, compact MOS transistor models should exhibit qualitatively correct physical behavior for drain current, terminal charges, noise, and all derivatives. Physics-based models may automatically embody the correct physical behavior for long-channel devices, but compact models of scaled transistors inevitably involve approximations that can introduce unphysical qualitative characteristics. Over time, several “benchmark tests” were developed to ensure that transistor characteristics predicted by a compact model satisfy the needs of the circuit designers, especially for analog and mixed-signal design. As the importance of RF CMOS circuits increases, the requirements for qualitatively correct physical behavior of compact MOSFET models are becoming more stringent (for example, it is now common to require the existence of fifth order derivatives) and several new benchmark tests, targeted for RF design needs, were developed. This chapter describes both traditional and newly developed MOSFET model benchmark tests and applies them to the PSP model.