This part is a kind of semiconductor called NK50ZFP.

Function of this product has STB9NK50ZFP.

Manufacturers : STMicroelectronics

Image and pinout :

Some of the text within the PDF file :

N-CHANNEL 500V - 0.72Ω - 7.2A TO-220/TO-220FP/D2PAK Zener-Protected SuperMESH™ Power MOSFET TYPE STP9NK50Z STP9NK50ZFP STB9NK50Z s s s s s s STP9NK50Z - STP9NK50ZFP STB9NK50Z VDSS 500 V 500 V 500 V RDS(on) < 0.85 Ω < 0.85 Ω < 0.85 Ω ID 7.2 A 7.2 A 7.2 A Pw 110 W 30 W 110 W 3 1 2 TYPICAL RDS(on) = 0.72 Ω EXTREMELY HIGH dv/dt CAPABILITY 100% AVALANCHE TESTED GATE CHARGE MINIMIZED VERY LOW INTRINSIC CAPACITANCES VERY GOOD MANUFACTURING REPEATIBILITY TO-220 TO-220FP 3 1 D2PAK DESCRIPTION The SuperMESH™ series is obtained through an extreme optimization of ST’s well established stripbased PowerMESH™ layout. In addition to pushing on-resistance significantly down, special care is taken to ensure a very good dv/dt capability for the most demanding [ ... ]

NK50ZFP PDF Datasheet Download