mmbt5551.pdf datasheet:

MMBT5551SOT-23 Features(TO-236) For Switching and Amplifier Applications. Silicon Epitaxial Chip 1 Base 2. Emitter 3. Collector Absolute Maximum Ratings (T =25 oC, unless otherwise noted)AParameter Symbol Value Unit Collector Base Voltage V 180 V CBO Collector Emitter Voltage V 160 V CEO Emitter Base Voltage V 6 V EBO Collector Current I 600 mA C Power Dissipation P 350 mW D Junction Temperature T 150 J Storage Temperature Range T -55 to 150 STGElectrical Characteristics(T =25 oC, unless otherwise noted)AParameter Symbol Min. Max. Unit DC Current Gain - - 80 at VCE = 5 V, IC = 1mA H 250 - FE at VCE = 5V, IC = 10 mA 80 - - at VCE=5V,IC=50mA 30 Collector Base Cutoff Current I - 50 nA CBO at VCB = 120 V Emitter Base Cutoff Current IEBO - 50 nA at VEB=4V Collector Base Breakdown Voltage