SEUSENSITIVITYOF POWERCONVERTERS WITHMOSFETSIN SPACE

Thispaperpresentstheresultsofan investigationintothesurvivability ofpowerMOSFETsin space. Seventy-two of thesedevicesarepresently in geosynchronous orbiton boardsixcommunications spacecraft, andoperating at 70Vwhichis 70%of the nominalbreakdownvoltage.No failures haveoccurred after94536device-days inspace. Theirradiation of discrete partsas wellas theprototypeflightpower converter,containing thesameparttypes,by iron particles witha LETof10MeV-cm2/mg, andan iron spectrumwitha maximumLETof 26showedtheseHi-Rel ("S")flightpartsto be relatively harderthanthe sametypeofdevicespreviously groundtested.This appearsto be theexplanation forthelackof failures inspace.