A high-frequency MOS transistor model and its effects on radio-frequency circuits

Accurate modeling and efficient parameter extraction of a small signal equi valent circuit of MOS transistors for high-frequency operation are presente d. The small-signal equivalent circuit is based on the quasi-static approxi mation which was found to be adequate up to 10 GHz for MOS transistors fabr icated by a 20 GHz cutoff frequency technology. The extrinsic components an d substrate coupling effects are properly included. Direct extraction is pe rformed by Y-parameter analysis on the equivalent circuit in the linear and saturation regions of operation. A low-noise amplifier is used to illustra te the effects on circuit performance due to accurate inclusion of extrinsi c components in the model. Good agreement between simulated results and mea sured data on high-frequency transistor characteristics has been achieved.