This part is a kind of semiconductor called 2SD5011.

Function of this product has Power Transistor.

Manufacturers : Inchange Semiconductor

Image and pinout :

Some of the text within the PDF file :

INCHANGE Semiconductor isc Product Specification isc Silicon NPN Power Transistor 2SD5011 DESCRIPTION ·High Breakdown Voltage: VCBO= 1500V (Min) ·High Switching Speed ·High Reliability ·Built-in Damper Diode APPLICATIONS ·Designed for color TV horizontal output applications ABSOLUTE MAXIMUM RATINGS(Ta=25℃) SYMBOL PARAMETER VCBO Collector-Base Voltage VCEO Collector-Emitter Voltage VEBO Emitter-Base Voltage w w s c s i . w VALUE UNIT 1500 V 800 V 6 V 3.5 A 10 A 50 W n c . i m e IC Collector Current- Continuous ICM Collector Current-Peak PC Collector Power Dissipation @ TC=25℃ TJ Junction Temperature 150 ℃ Tstg Storage Temperature Range -55~150 ℃ isc Website：www.iscsemi.cn INCHANGE Semiconductor isc Prod [ ... ]

2SD5011 PDF Datasheet Download