This part is a kind of semiconductor called B631K.

Function of this product has 2SB631K.

Manufacturers : Sanyo Semicon Device

Image and pinout :

Some of the text within the PDF file :

Ordering number:346G PNP/NPN Epitaxial Planar Silicon Transistor 2SB631,631K/2SD600,600K 100V/120V, 1A Low-Frequency Power Amplifier Applications Features · High breakdown voltage VCEO 100/120V, High current 1A. · Low saturation voltage, excellent hFE linearity. Package Dimensions unit:mm 2009B [2SB631, 631K/2SD600, 600K] ( ) : 2SB631, 631K 1 : Emitter 2 : Collector 3 : Base JEDEC : TO-126 Specifications Absolute Maximum Ratings at Ta = 25˚C Parameter Collector-to-Base Voltage Collector-to-Emitter Voltage Emitter-to-Base Voltage Collector Current Collector Current (Pulse) Collector Dissipation Junction Temperature Storage Temperature Symbol VCBO VCEO VEBO IC ICP PC Conditions 2SB631, D600 (–)100 (–)100 2SB631K, D600K (–)120 (–)120 (–)5 (–)1 (–)2 [ ... ]

B631K PDF Datasheet Download