This part is a kind of semiconductor called BH0170A.

Function of this product has FSBH0170A.

Manufacturers : Fairchild Semiconductor

Image and pinout :

Some of the text within the PDF file :

FSBH0F70A_F116, FSBH0170/0270/0370_F116 Green Mode Fairchild Power Switch (FPS™) April 2011 FSBH0F70A _F116, FSBH0170_F116, FSBH0270_F116, FSBH0370_F116 Green Mode Fairchild Power Switch (FPS™) Features                  Brownout Protection with Hysteresis Built-In 5ms Soft-Start Function Internal Avalanche-Rugged 700V SenseFET Low Acoustic Noise During Light-Load Operation High-Voltage Startup Linearly Decreasing PWM Frequency to 18KHz Peak-Current-Mode Control Cycle-by-Cycle Current Limiting Leading-Edge Blanking (LEB) Synchronized Slope Compensation Internal Open-Loop Protection VDD Under-Voltage Lockout (UVLO) VDD Over-Voltage Protection (OVP) Internal Auto-Restart Circuit (OVP, OTP) Constant Power Limit (Full AC Input Range) [ ... ]

BH0170A PDF Datasheet Download