RF front-end staple in a SOT-23-3
The Infineon BFR181E6327HTSA1 is an NPN silicon RF transistor. It delivers 18.5 dB small-signal gain with a noise figure of 0.9 dB to 1.2 dB across 900 MHz to 1.8 GHz. The 8 GHz transition frequency gives headroom for gain in the low-GHz range.
12 V rail, 20 mA collector — what that means for the bias
The 12 V collector-emitter breakdown sets the supply rail ceiling. Maximum collector current is 20 mA and power dissipation is 175 mW. Minimum DC current gain is 70 at 5 mA, 8 V.
PG-SOT23 package — board footprint and thermal
Supplier device package is PG-SOT23, the Infineon designation for the standard SOT-23-3. The TO-236-3 / SC-59 / SOT-23-3 case codes all map to the same three-lead footprint. Surface-mount assembly with the collector on the tab; the 150 °C junction temperature rating is typical for this class, but the 175 mW power limit means the board copper and airflow matter if you run near the maximum. No heatsink — just the PCB pad.
Active production, no obsolescence pressure
Infineon lists the BFR181E6327HTSA1 as Active product status. There is no last-time-buy notice, no NRND flag, and no announced end-of-life. ROHS3 compliant. For a BOM line that needs a reliable RF transistor for ongoing production, this part is still a standard catalog item — no sourcing urgency beyond normal lead-time management.