View mmbt918l datasheet:

MOTOROLA Order this document SEMICONDUCTOR TECHNICAL DATA by MMBT918LT1/D VHF/UHF Transistor MMBT918LT1 NPN Silicon COLLECTOR 3 1 BASE 3 2 EMITTER 1 MAXIMUM RATINGS 2 Rating Symbol Value Unit Collector–Emitter Voltage VCEO 15 Vdc CASE 318–08, STYLE 6 SOT–23 (TO–236AB) Collector–Base Voltage VCBO 30 Vdc Emitter–Base Voltage VEBO 3.0 Vdc Collector Current — Continuous IC 50 mAdc THERMAL CHARACTERISTICS Characteristic Symbol Max Unit Total Device Dissipation FR–5 Board,(1) PD 225 mW TA = 25°C Derate above 25°C 1.8 mW/°C Thermal Resistance, Junction to Ambient RqJA 556 °C/W Total Device Dissipation PD 300 mW Alumina Substrate,(2) TA = 25°C Derate above 25°C 2.4 mW/°C Thermal Resistance, Junction to Ambient RqJA 417 °C/W Junction and Storage Temperature TJ, Tst