irfp440a.pdf datasheet:

isc N-Channel MOSFET Transistor IRFP440A FEATURES Drain Current I = 8.5A@ T =25 D C Drain Source Voltage- V = 500V(Min) DSS Static Drain-Source On-Resistance R = 0.85 (Max) DS(on) Fast Switching 100% avalanche tested Minimum Lot-to-Lot variations for robust device performance and reliable operation DESCRIPTION Designed for use in switch mode power supplies and general purpose applications. ABSOLUTE MAXIMUM RATINGS(T =25 ) a SYMBOL PARAMETER VALUE UNIT V Drain-Source Voltage 500 V DSS V Gate-Source Voltage-Continuous 30 V GS I Drain Current-Continuous 8.5 A D I Drain Current-Single Pluse 34 A DM P Total Dissipation @T =25 162 W D C Max. Operating Junction Temperature -55 150 T J T Storage Temperature -55 150 stg THERMAL CHARACTERISTICS SYMBOL PARAMETER MAX UNIT /W R Thermal Resistance, Junction to Case 0.8