This part is a kind of semiconductor called AP3581A.

Function of this product has Single Phase Synchronous Buck PWM Controller.

Manufacturers : BCD

Image and pinout :

Some of the text within the PDF file :

OBSOLETE Data Sheet Single Phase Synchronous Buck PWM Controller AP3581A/B/C General Description The1AP3581A/B/C1is1a1compact1synchronous-rect ified buck controller specifically designed to operate from 5V/12V supply and deliver high-quality output voltage as low as 0.6V (AP3581A) or 0.8V (AP3581B/C). The AP3581A/B/C operates at fixed frequency of 300kHz (AP3581A/B) or 200kHz (AP3581C) and provides an optimal level of integration to reduce size and cost of the power supply. This controller integrates internal MOSFET drivers that support 12V+12V bootstrapped voltage for highefficiency power conversion. The bootstrap diode is built-in to simplify the circuit design and minimize external part count. This controller provides single feedback loop, voltage-mode control with fast transient re [ ... ]

AP3581A PDF Datasheet Download