This part is a kind of semiconductor called D637.

Function of this product has 2SD637.

Manufacturers : Panasonic

Image and pinout :

Some of the text within the PDF file :

Transistor 2SD637 Silicon NPN epitaxial planer type For low-power general amplification Unit: mm 6.9±0.1 1.5 2.5±0.1 1.0 1.0 2.4±0.2 2.0±0.2 3.5±0.1 s Features High foward current transfer ratio hFE. Low collector to emitter saturation voltage VCE(sat). q M type package allowing easy automatic and manual insertion as well as stand-alone fixing to the printed circuit board. q q 1.5 R0.9 R0.9 0.4 1.0±0.1 R 0. 0.85 (Ta=25˚C) Ratings 60 50 7 200 100 400 150 –55 ~ +150 Unit V V V mA mA mW ˚C ˚C 1:Base 2:Collector 3:Emitter 2.5 2.5 3 2 1 Parameter Collector to base voltage Collector to emitter voltage Emitter to base voltage Peak collector current Collector current Collector power dissipation Junction temperature Storage temperature Symbol VCBO VCEO VEBO [ ... ]

D637 PDF Datasheet Download