This part is a kind of semiconductor called 2SD1275.

Function of this product has Silicon NPN triple diffusion planar type Darlington(For power amplification).

Manufacturers : Panasonic Semiconductor

Image and pinout :

Some of the text within the PDF file :

Power Transistors 2SD1275, 2SD1275A Silicon NPN triple diffusion planar type Darlington 0.7±0.1 For power amplification Complementary to 2SB949 and 2SB949A 10.0±0.2 5.5±0.2 2.7±0.2 4.2±0.2 4.2±0.2 Unit: mm q q 16.7±0.3 q High foward current transfer ratio hFE High-speed switching Full-pack package which can be installed to the heat sink with one screw (TC=25˚C) Ratings 60 80 60 80 5 4 2 35 2 150 –55 to +150 Unit V 7.5±0.2 s Features φ3.1±0.1 4.0 14.0±0.5 s Absolute Maximum Ratings Parameter Collector to base voltage Collector to 2SD1275 2SD1275A 2SD1275 Symbol VCBO VCEO VEBO ICP IC PC Tj Tstg 1.4±0.1 1.3±0.2 Solder Dip 0.8±0.1 0.5 –0.1 +0.2 2.54±0.25 5.08±0.5 emitter voltage 2SD1275A Emitter to base voltage Peak collector current Collector curren [ ... ]

2SD1275 PDF Datasheet Download