This part is a kind of semiconductor called STP6NK90Z.
Function of this product has N-channel Power MOSFET.
Manufacturers : STMicroelectronics
Image and pinout :
Some of the text within the PDF file :
STP6NK90Z - STP6NK90ZFP STB6NK90Z - STW7NK90Z N-channel 900V - 1.56Ω - 5.8A - TO-220/TO-220FP/D2PAK/TO-247 Zener-protected SuperMESH™ Power MOSFET Features Type STP6NK90Z STP6NK90ZFP STB6NK90Z STW7NK90Z VDSS 900 V 900 V 900 V 900 V RDS(on) <2Ω <2Ω <2Ω <2Ω ID 5.8 A 5.8 A 5.8 A 5.8 A ■ Extremely high dv/dt capability ■ 100% avalanche tested ■ Gate charge minimized ■ Very low intrinsic capacitances ■ Very good manufacturing repeatability Description The SuperMESH™ series is obtained through an extreme optimization of ST’s well established strip-based 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 applications. Such series complements ST full range [ ... ]