Modeling of the MOS transistor for high frequency analog design

A high-frequency (HF) small-signal model is presented that is capable of describing accurately the MOS transistor (in saturation) at frequencies beyond the cutoff frequency. The model is carefully compared to other models. It is shown how all the circuit elements of the model can be measured. This measurement method uses S-parameter measurements, computer-controlled calibration techniques of the test setup and network analyzer, mathematical transformations of the S-parameters to other linear parameters, and extraction routines to fit the data towards the HF model. The model is finally used in the design of an HF optical transconductance amplifier to prove that this model is much more accurate than the classical models at higher frequencies.>