This part is a kind of semiconductor called MDD1903.

Function of this product has Single N-channel Trench MOSFET.

Manufacturers : MagnaChip

Image and pinout :

Some of the text within the PDF file :

MDD1903 – Single N-Channel Trench MOSFET 100V Preliminary – Subject to change without notice MDD1903 Single N-channel Trench MOSFET 100V, 11A, 120mΩ General Description The MDD1903 uses advanced MagnaChip’s MOSFET Technology, which provides high performance in on-state resistance, fast switching performance and excellent quality. MDD1903 is suitable device for DC/DC Converters and general purpose applications. Features  VDS = 100V  ID = 11A @VGS = 10V  RDS(ON) < 120mΩ @VGS = 10V < 135mΩ @VGS = 6.0V D G Absolute Maximum Ratings (Tc = 25oC) Drain-Source Voltage Gate-Source Voltage Continuous Drain Current (1) Characteristics Pulsed Drain Current Power Dissipation Junction and Storage Temperature Range Thermal Characteristics Characteristics Thermal Resistance, J [ ... ]

MDD1903 PDF Datasheet Download