This part is a kind of semiconductor called BFQ31A.

Function of this product has NPN SILICON PLANAR VHF/UHF TRANSISTOR.

Manufacturers : Zetex Semiconductors

Image and pinout :

Some of the text within the PDF file :

SOT23 NPN SILICON PLANAR VHF/UHF TRANSISTOR ISSUE 4 – MARCH 2001 PARTMARKING DETAILS BFQ31A – S4 BFQ31AR – S5 BFQ31A C B E ABSOLUTE MAXIMUM RATINGS. PARAMETER Collector-Base Voltage Collector-Emitter Voltage Emitter-Base Voltage Continuous Collector Current Base Current Power Dissipation at T amb=25°C Operating and Storage Temperature Range SYMBOL V CBO V CEO V EBO IC IB P tot T j:T stg VALUE 30 15 3 100 50 330 -55 to +150 UNIT V V V mA mA mW °C ELECTRICAL CHARACTERISTICS (at Tamb = 25°C). PARAMETER SYMBOL MIN. Collector-Base Breakdown Voltage Collector-Emitter Breakdown Voltage Emitter-Base Breakdown Voltage Collector Cut-Off Current Collector-Emitter Saturation Voltage Base-Emitter Saturation Voltage Static Forward Current Transfer Ratio Transition Frequency Output Capacita [ ... ]

BFQ31A PDF Datasheet Download