This part is a kind of semiconductor called WPM9435A.

Function of this product has MOSFET.

Manufacturers : WillSEMI

Image and pinout :

Some of the text within the PDF file :

WPM9435A Single P-Channel, -30V, -6.3A, Power MOSFET WPM9435A Http://www.sh-willsemi.com VDS (V) -30 Typical RDS(on) (mΩ) 33 @ VGS=-10V 43 @ VGS=-4.5V Descriptions The WPM9435A is P-Channel enhancement MOS Field Effect Transistor. Uses advanced trench technology and design to provide excellent RDS(ON) with low gate charge. This device is suitable for use in DC-DC conversion, power switch and charging circuit. Standard Product WPM9435A is Pb-free. Features (4) (3) (2) (1) SOP-8L DD 87 DD 65 12 SS 34 SG Pin configuration (Top view)  Trench Technology  Supper high density cell design  Excellent ON resistance  Extremely Low Threshold Voltage Applications  DC/DC converters  Power supply converters circuit  Load/Power Switching for portable device 9435 PA YW [ ... ]

WPM9435A PDF Datasheet Download