This part is a kind of semiconductor called FR9888C.

Function of this product has 340KHz Synchronous Step-Down DC/DC Converter.

Manufacturers : Fiti

Image and pinout :

Some of the text within the PDF file :

FR9888C 23V, 3.5A, 340KHz Synchronous Step-Down DC/DC Converter FEATURES High Efficiency up to 96% Low Rds(on) Integrated Power MOSFET Wide Input Voltage Range: 4.5V to 23V Adjustable Output Voltage Range: 0.925V to 20V Fixed 340KHz Switching Frequency Adjustable Soft-Start Cycle-by-Cycle Current Limit Input Under Voltage Lockout Over-Temperature Protection with Auto Recovery <1µA Shutdown Current TYPICAL APPLICATION CIRCUIT PIN DESCRIPTION NAME SOP8 DESCRIPTION BST 1 High Side Gate Drive Boost VIN 2 Power Supply Input Pin LX 3 Power Switching Output GND 4,9 Ground TYPICAL APPLICATION FB 5 Voltage Feedback Input Set-Top-Box (STB) COMP 6 Compensation Pin Television SHDN 7 Enable Input Distributed Power System SS 8 Soft-Start XDSL Modem PACKAGE 14 誠信、創�� [ ... ]

FR9888C PDF Datasheet Download