SI73 TrenchFET® Power MOSFETs Vishay Semiconductors SI73 TrenchFET® Power MOSFETs are available in a new low thermal resistance PowerPAK® package with a low 1.07mm profile. The TrenchFET® Power MOSFETs are 100% Rg/UIS tested and halogen-free. These SI73 power MOSFETs are ideally used in DC/DC converters.