This part is a kind of semiconductor called W20NC50.

Function of this product has STW20NC50.

Manufacturers : STMicroelectronics

Image and pinout :

Some of the text within the PDF file :

N-CHANNEL 500V - 0.22Ω - 18.4A TO-247 PowerMesh™II MOSFET TYPE STW20NC50 s TYPICAL s s s s STW20NC50 VDSS 500V RDS(on) < 0.27Ω ID 18.4A RDS(on) = 0.22Ω EXTREMELY HIGH dv/dt CAPABILITY 100% AVALANCHE TESTED NEW HIGH VOLTAGE BENCHMARK GATE CHARGE MINIMIZED 2 1 3 DESCRIPTION The PowerMESH™II is the evolution of the first generation of MESH OVERLAY™. The layout refinements introduced greatly improve the Ron*area figure of merit while keeping the device at the leading edge for what concerns swithing speed, gate charge and ruggedness. TO-247 INTERNAL SCHEMATIC DIAGRAM APPLICATIONS SWITH MODE LOW POWER SUPPLIES (SMPS) s HIGH CURRENT, HIGH SPEED SWITCHING s DC-AC CONVERTERS FOR WELDING EQUIPMENT AND UNINTERRUPTIBLE POWER SUPPLIES AND MOTOR DRIVES s ABSOLU [ ... ]

W20NC50 PDF Datasheet Download