a bias circuit for a radio frequency linear power amplifier includes an input for selecting an operating mode varying in quiescent current of an output transistor . a sensor senses a current through the output transistor and a circuit biases the output transistor for maintaining linear performance in each of mode over a range of temperatures . a filter attenuates noise generated within the linear power amplifier . a tank circuit at the collector of a power radio frequency transistor , having an inductor capable of handling the collector current , resonating with a capacitor at the design frequency , permits a reduction in the required inductance and therefore higher levels of integration .