This part is a kind of semiconductor called MDF4N65B.
Function of this product has N-Channel MOSFET.
Manufacturers : MagnaChip
Image and pinout :

Some of the text within the PDF file :
MDF4N65B N-channel MOSFET 650V MDF4N65B N-Channel MOSFET 650V, 4.0A, 2.2Ω General Description These N-channel MOSFET are produced using advanced MagnaChip’s MOSFET Technology, which provides low onstate resistance, high switching performance and excellent quality. These devices are suitable device for SMPS, high Speed switching and general purpose applications. Features VDS = 650V ID = 4.0A RDS(ON) ≤ 2.2 Ω @ VGS = 10V @ VGS = 10V Applications Power Supply PFC High Current, High Speed Switching D TO-220F MDF Series 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) Juncti [ ... ]
MDF4N65B PDF Datasheet Download
