This part is a kind of semiconductor called MDS1521.

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

Manufacturers : MagnaChip

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Some of the text within the PDF file :

MDS1521 – Single N-Channel Trench MOSFET 30V MDS1521 Single N-channel Trench MOSFET 30V, 28.2A, 4.0mΩ General Description The MDS1521 uses advanced MagnaChip’s MOSFET Technology, which provides high performance in on-state resistance, fast switching performance and excellent quality. MDS1521 is suitable for DC/DC converter and general purpose applications. Features VDS = 30V ID = 28.2A @VGS = 10V RDS(ON) < 4.0mΩ @VGS = 10V < 5.5mΩ @VGS = 4.5V 100% UIL Tested 100% Rg Tested 5(D) 6(D) 7(D) 8(D) 4(G) 3(S) 2(S) 1(S) Absolute Maximum Ratings (Ta = 25oC) Drain-Source Voltage Gate-Source Voltage Characteristics Continuous Drain Current (1) Pulsed Drain Current Power Dissipation Single Pulse Avalanche Energy (2) Junction and Storage Temperature Range TC=25oC TC=70oC TA=25oC T [ ... ]

MDS1521 PDF Datasheet Download