This part is a kind of semiconductor called AP9T18GH-HF.

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

Manufacturers : Advanced Power Electronics

Image and pinout :

Some of the text within the PDF file :

Advanced Power Electronics Corp. AP9T18GH-HF Halogen-Free Product N-CHANNEL ENHANCEMENT MODE POWER MOSFET ▼ Low Gate Charge ▼ Capable of 2.5V Gate Drive ▼ Fast Switching Characteristic ▼ RoHS Compliant & Halogen-Free D G S Description AP9T18 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 TO-252 package is widely preferred for all commercial-industrial surface mount applications using infrared reflow technique and suited for high current application due to the low connection resistance. BVDSS RDS(ON) ID 20V 14mΩ 38A G DS TO-252(H) Absolute Symbol Maximum Ra [ ... ]

AP9T18GH-HF PDF Datasheet Download