2sd2100.pdf datasheet:

SMD Type TransistorsNPN Transistors2SD21001.70 0.1 Features Low saturation voltageCollector Large current cappacity0.42 0.1 Complementary to 2SB1397 0.46 0.1 Base1.BaseRBE2.Collector3.EmitterEmitter Absolute Maximum Ratings Ta = 25Parameter Symbol Rating Unit Collector - Base Voltage VCBO 25 Collector - Emitter Voltage VCEO 20 V Emitter - Base Voltage VEBO 6 Collector Current - Continuous IC 2A Collector Current - Pulse ICP 4 Collector Power Dissipation PC 1.3 W Junction Temperature TJ 150 Storage Temperature Range Tstg -55 to 150 Electrical Characteristics Ta = 25Parameter Symbol Test Conditions Min Typ Max Unit Collector- base breakdown voltage VCBO Ic= 100 uA IE= 0 25 Collector- emitter breakdown voltage VCEO Ic= 1 mA RBE= 20 V Emitter - base breakdown voltage VEBO IE= 100 uA