This part is a kind of semiconductor called AP3503E.

Function of this product has 3A Synchronous DC-DC Buck Converter.

Manufacturers : BCD

Image and pinout :

Some of the text within the PDF file :

Preliminary Datasheet 340kHz, 3A Synchronous DC-DC Buck Converter AP3503E General Description The AP3503E is a 340kHz fixed frequency, current mode, PWM synchronous buck (step-down) DC-DC converter, capable of driving a 3A load with high efficiency, excellent line and load regulation. The AP3503E exhibits high efficiency at light load. The device integrates N-channel power MOSFET switches with low on-resistance. Current mode control provides fast transient response and cycle-by-cycle current limit. The AP3503E employs complete protection to ensure system security. Including output Over Voltage Protection, input Under Voltage Lock Out, programmable Soft Start, Over Temperature Protection and hiccup mode Short Circuit Protection. This IC is available in PSOP-8 package. Features • Input [ ... ]

AP3503E PDF Datasheet Download