fqs4903.pdf datasheet:

May 2000TMQFETQFETQFETQFET 500V DuaI N-ChanneI MOSFETGeneraI Description FeaturesThese N-Channel enhancement mode power field effect 0.37A, 500V, RDS(on) = 6.2 @VGS = 10 Vtransistors are produced using Fairchilds proprietary, Low gate charge ( typical 6.3 nC)planar stripe, DMOS technology. Low Crss ( typical 4.5 pF)This advanced technology has been especially tailored to Fast switchingminimize on-state resistance, provide superior switching Improved dv/dt capabilityperformance, and withstand high energy pulse in theavalanche and commutation mode. These devices are wellsuited for high efficiency switch mode power supply, powerfactor correction, electronic lamp ballast based on halfbridge. pin #1 AbsoIute Maximum Ratings T = 25C unless otherwise notedSymboI Parameter FQS4903 UnitsVDSS