SiGe RF Bipolar Transistors, Infineon A range of ultra-low-noise wideband NPN bipolar RF transistors from Infineon. These hetero-junction bipolar devices utilize Infineon’s silicon germanium carbon (SiGe:C) material technology and are especially suited for use mobile applications in which low power consumption is a key requirement. With typical transition frequencies of up to 65 GHz these devices offer high power gain at frequencies of up to 10 GHz when used in amplifier applications. The transistors include internal circuitry for ESD and excessive RF input power protection.