A power MOSFET is provided on a semiconductor die to withstand radiation exposure. The semiconductor die is mounted on a die flag of a leadframe. The MOSFET includes a substrate and epitaxial layer formed over the substrate. A source region is formed in a surface of the semiconductor die. The source region is coupled to the die flag. A contact pad is formed on the source region. A base region is formed in the surface of the semiconductor die adjacent to the source region. The base region is electrically connected to the contact pad. A drain region is formed in the surface of the semiconductor die. The drain region is coupled to a first wire bond pad on the leadframe. A gate structure is formed over a channel between the source region and drain region. The gate structure is coupled to a second wire bond pad on the leadframe.