Reconfigurable power amplifiers with controllable input capacitance

A method of amplification in a mobile device, the method comprising:

• generating a first radio frequency signal of a first frequency band and a second radio frequency signal of a second frequency band using a transceiver;
• selecting one of the first radio frequency signal or the second radio frequency signal as a selected radio frequency signal based on a band control signal;
• amplifying the selected radio frequency signal using a push-pull power amplifier that includes an input balun, an output balun, and a pair of amplifiers coupled between the input balun and the output balun;
• and
• controlling an input capacitance of the pair of amplifiers based on the band control signal.

A push-pull power amplifier comprising:

• an input selection circuit configured to provide a selected radio frequency signal based on a band control signal, the selected radio frequency signal chosen from one of a first radio frequency signal of a first frequency band or a second radio frequency signal of a second frequency band;
• an input balun;
• an output balun;
• and
• a pair of amplifiers coupled between the input balun and the output balun and operable to amplify the selected radio frequency signal, the band control signal operable to control an input capacitance of the pair of amplifiers.