X-band NPN for low-noise front-ends
The Infineon BFP420E6327 is a silicon NPN RF transistor designed for X-band low-noise amplifier and oscillator stages up to 25 GHz transition frequency. Its 21 dB gain at a typical bias point gives one stage enough headroom for most receiver front-ends before the mixer. The 1.1 dB noise figure at 1.8 GHz keeps the system noise floor low — useful for cellular infrastructure, satellite downconverters, and test equipment front-ends. Collector-emitter breakdown is 5 V, so keep the supply rail under that; this is a low-voltage signal transistor, not a power device. Maximum collector current is 35 mA, and total power dissipation is 160 mW — sized for small-signal duty, not final-stage amplification.