This part is a kind of semiconductor called BFR91.

Function of this product has Silicon NPN Planar RF Transistor.

Manufacturers : Vishay Telefunken

Image and pinout :

Some of the text within the PDF file :

BFR91 Vishay Telefunken Silicon NPN Planar RF Transistor Electrostatic sensitive device. Observe precautions for handling. Applications RF amplifier up to GHz range specially for wide band antenna amplifier. Features D High power gain D Low noise figure D High transition frequency 3 2 94 9308 13623 1 BFR91 Marking: BFR91 Plastic case (TO 50) 1 = Collector, 2 = Emitter, 3 = Base Absolute Maximum Ratings Tamb = 25_C, unless otherwise specified Parameter Collector-base voltage Collector-emitter voltage Emitter-base voltage Collector current Total power dissipation Junction temperature Storage temperature range Test Conditions Symbol VCBO VCEO VEBO IC Ptot Tj Tstg Value 20 12 2 50 300 150 –65 to +150 Unit V V V mA mW °C °C Tamb ≤ 60 °C Maximum Thermal Resistance Tamb = 25_C, [ ... ]

BFR91 PDF Datasheet Download