This part is a kind of semiconductor called AP4439GMT-HF.

Function of this product has P-CHANNEL ENHANCEMENT MODE POWER MOSFET.

Manufacturers : Advanced Power Electronics

Image and pinout :

Some of the text within the PDF file :

Advanced Power Electronics Corp. AP4439GMT-HF Halogen-Free Product P-CHANNEL ENHANCEMENT MODE POWER MOSFET ▼ Simple Drive Requirement ▼ SO-8 Compatible D ▼ Lower Gate Charge ▼ RoHS Compliant & Halogen-Free G S Description AP4439 series are from Advanced Power innovated design and silicon process technology to achieve the lowest possible on-resistance and fast switching performance. It provides the designer with an extreme efficient device for use in a wide range of power applications. The PMPAK® 5x6 package is special for voltage conversion application using standard infrared reflow technique with the backside heat sink to achieve the good thermal performance. BVDSS RDS(ON) ID -30V 10mΩ -58A D D D D S S S G PMPAK® 5x6 Absolute Maximum Ratings@Tj=25oC(unless otherw [ ... ]

AP4439GMT-HF PDF Datasheet Download