This part is a kind of semiconductor called APW7089.

Function of this product has Asynchronous Step-Down Converter.

Manufacturers : ANPEC

Image and pinout :

Some of the text within the PDF file :

APW7089 4A, 26V, 380kHz, Asynchronous Step-Down Converter Features General Description • Wide Input Voltage from 4.5V to 26V • Output Current up to 4A • Adjustable Output Voltage from 0.8V to 90% V IN - 0.8V Reference Voltage - ±2.5% System Accuracy • 80mΩ Integrated P-Channel Power MOSFET • High Efficiency up to 91% - Pulse-Skipping Mode (PSM) / PWM Mode Op- eration • Current-Mode Operation - Stable with Ceramic Output Capacitors - Fast Transient Response • Power-On-Reset Monitoring • Fixed 380kHz Switching Frequency in PWM Mode • Built-in Digital Soft-Start • Output Current-Limit Protection with Frequency Foldback • 70% Under-Voltage Protection • Over-Temperature Protection • <5µA Quiescent Current During Shutdown • Thermal-Enhanced SOP-8P Pa [ ... ]

APW7089 PDF Datasheet Download