Abstract
In this paper, we propose a new electro-thermal model of power RF LDMOS transistor implemented in Agilent's ADS, using symbolic defined device (SDD). The proposed model takes into account the thermal effects and influence of temperature on the I-V characteristics, by providing three thermal capacitances and three thermal resistances, which represent the heat flow from the chip to the ambient air (thermal network). It allows us to study temperature dependent shifts for some macroscopic parameters such as the threshold voltage (V/sub t/), the transconductance (g/sub m/), the conductance (g/sub d/) and the on-state resistance (R/sub ds-on/).