2SC3309 Inchange Semic, Silicon NPN Power Switching Transistor, 
Vcbo 500V, Vceo 400V, Ic 2A, Tc 25°C 20W, 100MHz, 
Case type: TO-220F-ISOL, 

Marking: C3309, 
BCE 

Switching regulators and high voltage switching, 
High speed DC-DC converter application..