View stw20nb50 datasheet:

STW20NB50 ? N - CHANNEL 500V - 0.22? - 20A - TO-247 PowerMESH? MOSFET TYPE VDSS RDS(on) ID STW20NB50 500 V < 0.25 ? 20 A TYPICAL R = 0.22 ? DS(on) EXTREMELY HIGH dv/dt CAPABILITY ± 30V GATE TO SOURCE VOLTAGE RATING 100% AVALANCHE TESTED REPETITIVE AVALANCHE DATA AT 100oC VERY LOW INTRINSIC CAPACITANCES 3 GATE CHARGE MINIMIZED 2 1 DESCRIPTION Using the latest high voltage technology, TO-247 STMicroelectronics has designed an advanced family of power Mosfets with outstanding performances. The new patent pending strip layout coupled with the Company’s proprietary edge termination structure, gives the lowest INTERNAL SCHEMATIC DIAGRAM R (on) per area, exceptional avalanche and DS dv/dt capabilities and unrivalled gate charge and switching characteristics.