This part is a kind of semiconductor called FR9802.

Function of this product has 1.2MHz Synchronous Step-Down DC/DC Converter.

Manufacturers : Fiti

Image and pinout :

Some of the text within the PDF file :

FR9802 21V, 1.5A, 1.2MHz Synchronous Step-Down DC/DC Converter FEATURES High Efficiency up to 94% Low Rds(on) Integrated Power MOSFET Internal Compensation Function Wide Input Voltage Range: 4.5V to 21V Adjustable Output Voltage from 0.8V to 16.8V 1.5A Output Current Fixed 1.2MHz Switching Frequency Current Mode Operation Cycle-by-Cycle Current Limit Over-Temperature Protection with Auto Recovery Output Overvoltage Protection Under Voltage Lockout <1µA Shutdown Current TYPICAL APPLICATION CIRCUIT PIN DESCRIPTION NAME SOT23-6 BST GND FB SHDN VIN LX 1 2 3 4 5 6 DESCRIPTION High Side Gate Drive Boost Ground Voltage Feedback Input Enable Input Power Supply Input Power Switching Output TYPICAL APPLICATION STB (Set-Top-Box) LCD Display, TV Distributed Power System Networking, XDSL Modem [ ... ]

FR9802 PDF Datasheet Download