Practical considerations of Trench MOSFET stability when operating in linear mode, application note (PDF!) from Fairchild Semiconductor
This application note focuses on the factors affecting the thermal instability condition of a trench MOSFET device in Linear Mode. In particular, it studies the phenomenon when the drain current (Id) focusing process occurs that leads to a localized hot spot to the device. Several devices were tested to failure to determine the degree of damage within the die and to differentiate the failure signatures under diferent test conditions. The practical analysis of the device Forward-Biased Safe Operating Area (FBSOA) performance in Linear Mode is presented. It is evaluated in terms of finding the Zero Temparature Coefficient (ZTC) value of the device based on its Id vs. Vgs performance characteristic curves.