US Patent 7889005 Controllable amplifier and the use thereof

A controllable amplifier amplifies a radiofrequency input signal on the basis of a control signal. A current path is formed between a supply potential connection and a reference potential connection. The current path includes an amplifier transistor and a cascode transistor, the cascode transistor being connected to the input for supplying the control signal. The output power of the amplifier is controlled using the cascode transistor, as a result of which a low power consumption is achieved in conjunction with good noise properties.