This part is a kind of semiconductor called MDF4N60B.

Function of this product has N-Channel Trench MOSFET.

Manufacturers : MagnaChip

Image and pinout :

Some of the text within the PDF file :

MDF4N60B N-channel MOSFET 600V MDF4N60B N-Channel MOSFET 600V, 4.6A, 2.0Ω 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 = 600V  ID = 4.6A  RDS(ON) ≤ 2.0Ω @ VGS = 10V @ VGS = 10V Applications  Power Supply  PFC  High Current, High Speed Switching D TO-220F MDF Series G 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 A [ ... ]

MDF4N60B PDF Datasheet Download