View bf840 datasheet:

NPN Silicon RF Transistors BF 840 BF 841 Suitable for common emitter RF, IF amplifiers Low collector-base capacitance due to contact shield diffusion Low output conductance Type Marking Ordering Code Pin Configuration Package1) 1 2 3 BF 840 NC Q62702-F1240 B E C SOT-23 BF 841 ND Q62702-F1287 Maximum Ratings Parameter Symbol Values Unit Collector-emitter voltage VCE0 40 V Collector-base voltage VCB0 40 Emitter-base voltage VEB0 4 Collector current IC 25 mA Base current IB 2 Total power dissipation, TA ? 25 ?C2) Ptot 280 mW Junction temperature Tj 150 ?C Storage temperature range Tstg – 65 … + 150 Thermal Resistance Rth JA ? 450 K/W Junction - ambient2) 1) For detailed information see chapter Package Outlines. 2) Package mounted on alumina 15 mm ? 16.7 mm ? 0.7 m