This part is a kind of semiconductor called AP2953A.

Function of this product has 18V Synchronous Rectified Step-Down Converter.

Manufacturers : Chipown

Image and pinout :

Some of the text within the PDF file :

AP2953A Description The AP2953A is a monolithic synchronous buck regulator. The device integrates 100mΩ MOSFETS that provide 3A continuous load current over a wide operating input voltage of 4.75V to 18V. Current mode control provides fast transient response and cycle-by-cycle current limit. An adjustable soft-start prevents inrush current at turn-on. In shutdown mode, the supply current drops below 1μA. This device, available in an 8-pin SOP package, provides a very compact system solution with minimal reliance on external components. Applications  Distributed Power Systems  Networking Systems  FPGA, DSP, ASIC Power Supplies  Green Electronics/ Appliances  Notebook Computers Chipown 3A, 18V Synchronous Rectified Step-Down Converter Features  3A Output Current  Wi [ ... ]

AP2953A PDF Datasheet Download