This part is a kind of semiconductor called D5N50F.

Function of this product has N-Channel MOSFET.

Manufacturers : Fairchild Semiconductor

Image and pinout :

Some of the text within the PDF file :

FDD5N50F N-Channel MOSFET, FRFET FDD5N50F N-Channel MOSFET, FRFET 500V, 3.5A, 1.55Ω Features • RDS(on) = 1.25Ω ( Typ.)@ VGS = 10V, ID = 1.75A • Low gate charge ( Typ. 11nC) • Low Crss ( Typ. 5pF) • Fast switching • 100% avalanche tested • Improved dv/dt capability • RoHS compliant December 2007 UniFETTM tm Description These N-Channel enhancement mode power field effect transistors are produced using Fairchild’s proprietary, planar stripe, DMOS technology. This advanced technology has been especially tailored to minimize on-state resistance, provide superior switching performance, and withstand high energy pluse in the avalanche and commutation mode. These devices are well suited for high efficient switched mode power suppliesand active power factorcorrection. D GD S [ ... ]

D5N50F PDF Datasheet Download