This part is a kind of semiconductor called STR-X6757.

Function of this product has Off-Line Quasi-Resonant Switching Regulators.

Manufacturers : Sanken

Image and pinout :

Some of the text within the PDF file :

STR-X6757 Off-Line Quasi-Resonant Switching Regulators Features and Benefits ▪ Quasi-resonant topology IC  Low EMI noise and soft switching ▪ Bottom-skip mode  Improved system efficiency over the entire output load by avoiding increase of switching frequency ▪ Auto-Standby mode  Lowers input power at very light output load condition ▪ Avalanche-guaranteed MOSFET  Improves system-level reliability and does not require VDSS derating ▪ 650 VDSS / 0.62 Ω RDS(on) ▪ Various protections  Improved system-level reliability ▫ Pulse-by-pulse drain overcurrent limiting ▫ Overvoltage Protection (bias winding voltage sensing), with latch ▫ Overload Protection with latch ▫ Maximum on-time limit Package: 7-Pin TO-3P Description The STR-X6757 is a quasi-resonant topolo [ ... ]

STR-X6757 PDF Datasheet Download