Integration of thermal effects into a table-based large-signal FET model

This paper presents how a conventional isothermal table-based large-signal FET model can be enhanced to cover the influence of channel temperature variations engendered both by ambient temperature changes and by dynamic device self-heating. The drain current temperature dependence is modelled using a single-parameter analytic expression. Examples of an 0.5μm gate MESFET are given, pointing out the relevance of temperature-dependent modelling also for low-power trnsistors. The analysis shows that temperature induced changes of the electron saturation velocity are to a strong degree responsible for the observed differences between DC and RE I/V-characteristics.