This part is a kind of semiconductor called MDF18N50B.

Function of this product has N-Channel MOSFET.

Manufacturers : MagnaChip

Image and pinout :

Some of the text within the PDF file :

MDP1850B / MDF18N50B N-channel MOSFET 500V MDP18N50B / MDF18N50B N-Channel MOSFET 500V, 18.0 A, 0.27Ω General Description The MDP/F18N50B uses advanced Magnachip’s MOSFET Technology, which provides low on-state resistance, high switching performance and excellent quality. MDP/F18N50B is suitable device for SMPS, HID and general purpose applications. Features VDS = 500V ID = 18.0A RDS(ON) ≤ 0.27Ω @VGS = 10V @VGS = 10V Applications Power Supply PFC Ballast Absolute Maximum Ratings (Ta = 25oC) Drain-Source Voltage Gate-Source Voltage Characteristics Continuous Drain Current Pulsed Drain Current(1) Power Dissipation Repetitive Avalanche Energy(1) Peak Diode Recovery dv/dt(3) Single Pulse Avalanche Energy(4) Junction and Storage Temperature Range ※ Id limited by maximum junc [ ... ]

MDF18N50B PDF Datasheet Download