SEU Sensitivity of Power Converters with MOSFETs in Space

This paper presents the results of an investigation into the survivability of power MOSFETs in space. Seventy-two of these devices are presently in geosynchronous orbit on board six communications spacecraft, and operating at 70V which is 70% of the nominal breakdown voltage. No failures have occurred after 94536 device-days in space. The irradiation of discrete parts as well as the prototype flight power converter, containing the same part types, by iron particles with a LET of 10 MeV-cm2/mg, and an iron spectrum with a maximum LET of 26 showed these Hi-Rel ("S") flight parts to be relatively harder than the same type of devices previously ground tested. This appears to be the explanation for the lack of failures in space.