This part is a kind of semiconductor called BF517.

Function of this product has NPN Silicon RF Transistor.

Manufacturers : Infineon Technologies AG

Image and pinout :

Some of the text within the PDF file :

BF 517 NPN Silicon RF Transistor
For amplifier and oscillator 3 applications in TV-tuners 2 1 VPS05161 Type BF 517 Maximum Ratings Parameter Marking LRs 1=B Pin Configuration 2=E Symbol VCEO VCBO VEBO IC ICM Ptot Tj TA Tstg Package SOT-23 Value 15 20 2.5 25 50 280 150 -65 ... 150 -65 ... 150 mW °C mA Unit V 3=C Collector-emitter voltage Collector-base voltage Emitter-base voltage Collector current Peak collector current, f
10 MHz Total power dissipation, TS  55 °C F) Junction temperature Ambient temperature Storage temperature Thermal Resistance Junction - soldering point RthJS
340 K/W 1T is measured on the collector lead at the soldering point to the pcb S 1 Oct-26-1999 BF 517 Electrical Characteristics at TA = 25 °C, unless otherwise specified. Parameter Symbol [ ... ]

BF517 PDF Datasheet Download