X Band HBT Driver Amplifier. The CHA5014 chip is a monolithic two-stage medium power amplifier designed for X band applications. Moreover this amplifier is relevant for systems that require an output power weakly sensitive to temperature. This device is manufactured using a GalnP HBT process, including via holes through the substrate and air bridges. A nitride layer protects the transistors and the passive components. A special control circuit is implemented to stabilize the output power in temperature.