This part is a kind of semiconductor called DAP011.
Function of this product has PWM Current-Mode Controller.
Manufacturers : ON Semiconductor
Image and pinout :
Some of the text within the PDF file :
Customer Specific Device from ON Semiconductor DAP011/DAP011C PWM Current−Mode Controller for High−Power Universal Off−Line Supplies • • • • • • 5.0 V – 5.0 mA Reference Voltage Internal Temperature Shutdown Direct Optocoupler Connection Extremely Low No−Load Standby Power Adjustable Soft−Start This is a Pb−Free Device* Housed in an SO−14 package, the DAP011/DAP011C represents an enhanced version of the Maximus, DAP008, controller. Due to its high drive capability, SpeedKing drives large gate−charge MOSFETs which, together with internal ramp compensation and a user selectable frequency jittering, ease the design of modern AC/DC adapters. With an internal structure operating at a fixed 65/100 kHz frequency, the controller directly connects to the high−voltag [ ... ]