Dynamic SOA of power MOSFETs

With the increase in operating frequency as well as voltage and current levels, power devices have to sustain a number of stress causing phenomena. For proper selection for an application, the specifications for the device need to given with emphasis on the kind of stresses it will be subjected to in the application. In that respect, the data-sheet specifications are incomplete in that they fail to predict the safe operating area of the device in the actual operating conditions resulting in field failures. Long-term effects of stresses including the degradation of the device characteristics with “age in an application” needs to be characterized. From that view a dynamic SOA is proposed. This includes an experimentally determined factor, which varies with the age of the device as per the stresses encountered by the device. The variation is modeled for different applications. It is expected to aid greatly in specific device selection for an application