BFPx4 RF Transistors Infineon BFPx4 RF Transistors provide the designer the best possible performance, superior flexibility and price/performance ratio. These are widely used for new emerging wireless applications, where the system specification is not yet firmly established. The BFxx Low Noise Amplifiers (LNAs) include devices suitable for use from AM over VHF/UHF up to 14GHz. These are the latest LNA innovations based on Infineon's reliable high volume 80GHz fT silicon germanium carbon (SiGe:C) heterojunction bipolar technology. They combine uncompromised RF performance with outstanding robustness against high RF input power overdrive and ESD.