This part is a kind of semiconductor called KA5L0380.

Function of this product has Fairchild Power Switch(FPS).

Manufacturers : Fairchild

Image and pinout :

Some of the text within the PDF file :

www.fairchildsemi.com KA5H0380R/KA5M0380R/KA5L0380R SPS Features • • • • • • • • • Precision fixed operating frequency (100/67/50kHz) Low start-up current(typ. 100uA) Pulse by pulse current limiting Over current protection Over voltage protecton (Min. 25V) Internal thermal shutdown function Under voltage lockout Internal high voltage sense FET Auto-restart mode Description The SPS product family is specially designed for an off-line SMPS with minimal external components. The SPS consist of high voltage power SenseFET and current mode PWM IC. Included PWM controller features integrated fixed frequency oscillator, under voltage lock-out, leading edge blanking, optimized gate turn-on/turn-off driver, thermal shutdown protection, over voltage protection, and temperature co [ ... ]

KA5L0380 PDF Datasheet Download