Part Number : STR-G6351
Function :STR-G6351 Switching Regulator (LF1129)
Manufacturer : Sanken Electric co.,ltd.
Pinout : 
Description
Hybrid IC type STR-G6351 for switching regulators.
http://www.electronica-pt.com/datasheets/ps/STR-G6351.pdf
Datasheet PDF Download
Other datasheets in the file : G6351, STR-G6351, STRG6351