This part is a kind of semiconductor called 2SD1691.

Function of this product has LOW COLLECTOR SATURATION VOLTAGE LARGE CURRENT.

Manufacturers : UTC

Image and pinout :

Some of the text within the PDF file :

UTC 2SD1691 NPN EPITAXIAL SILICON TRANSISTOR LOW COLLECTOR SATURATION VOLTAGE LARGE CURRENT FEATURES *High Power Dissipation: Pc=1.5W(Ta=25℃) *Complementary to 2SB1151 1 TO-126C 1:EMITTER 2:COLLECTOR 3:BASE ABSOLUTE MAXIMUM RATINGS (Ta=25 ℃) PARAMETER Collector-Base Voltage Collector-Emitter Voltage Emitter-Base Voltage Collector Current Base Current Collector Power Dissipation Ta=25℃ Tc=25℃ DC Pulse (Note 1) VCBO VCEO VEBO Ic Icp IB Pc Tj Tstg SYMBOL RATING 60 60 7 5 8 1 1.5 20 150 -55 ~ +150 UNIT V V V A A W ℃ ℃ Junction Temperature Storage Temperature Range Note 1 :PW≦10ms,Duty Cycle≦50% ELECTRICAL CHARACTERISTICS(Ta=25℃,unless otherwise specified ) CHARACTERISTIC Collector Cut-off Current Emitter Cut-off Current DC Current Gain SYMBOL I [ ... ]

2SD1691 PDF Datasheet Download