Compensating for non-linear capacitance effects in a power amplifier

A power amplifier comprising:

• a gain stage having first and second complementary amplifiers, the gain stage to receive a differential input signal on a differential input line and to output a differential amplified signal;
• a first compensation stage having a first compensation device coupled to a first amplifier of the first complementary amplifier and a second compensation device coupled to a first amplifier of the second complementary amplifier;
• and
• a second compensation stage having a first compensation device coupled to a second amplifier of the first complementary amplifier and a second compensation device coupled to a second amplifier of the second complementary amplifier, wherein each compensation device is to compensate for a change in capacitance of the corresponding amplifier when the differential input signal is in a predetermined transition region of an input range.

A method comprising:

• detecting an amplitude of an input signal into a gain stage;
• determining an amount of capacitance to be coupled to the gain stage responsive to the detected amplitude, wherein the capacitance is to compensate for a non-linear phase response of the gain stage to the input signal;
• and
• controlling a controllable element to couple the determined amount of capacitance to the gain stage.

A power amplifier comprising:

• a first gain stage having a complementary amplifier, the first gain stage to receive a radio frequency (RF) input signal on an input line and to output an amplified RF signal;
• a first compensation device coupled to a first gain device of the complementary amplifier and a second compensation device coupled to a second gain device of the complementary amplifier, wherein each compensation device is to decrease a magnitude of a rate of change in capacitance of the corresponding gain device when a level of the RF input signal causes an input level to the corresponding gain device to be substantially around a threshold voltage of the corresponding gain device;
• and
• a bias generator to provide a bias voltage to the first and second compensation devices, wherein the bias generator is to generate at least one bias voltage to enable a capacitance of the first and second compensation devices to be substantially equal and opposite to the capacitance change in the corresponding gain device substantially around the threshold voltage.