This part is a kind of semiconductor called PFV218N50.

Function of this product has 500V N-Channel MOSFET.

Manufacturers : Fairchild Semiconductor

Image and pinout :

Some of the text within the PDF file :

FQP18N50V2/FQPF18N50V2 500V N-Channel MOSFET QFET® FQP18N50V2/FQPF18N50V2 500V N-Channel MOSFET Features • 550V @TJ = 150°C • Typ. RDS(on) = 0.265Ω @VGS = 10 V • Low gate charge (typical 42 nC) • Low Crss (typical 11 pF) • Fast switching • 100% avalanche tested • Improved dv/dt capability 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 pulse in the avalanche and commutation mode. These devices are well suited for high efficient switched mode power supplies, active power factor correction, electronic lamp ballast b [ ... ]

PFV218N50 PDF Datasheet Download