Skyworks Solutions, Inc.
Power amplifier noise suppression using feedback

Abstract:

A power amplifier system can include a power amplifier that provides amplification to a radio frequency signal associated with a first frequency band and outputs an amplified radio frequency signal. An acoustic wave bandpass filter such as a surface acoustic wave or bulk acoustic wave bandpass filter is arranged in a feedback configuration with respect to the power amplifier. The filter can pass through a portion of the amplified radio frequency signal corresponding to a second frequency to provide negative feedback to the power amplifier, resulting in a reduction in an amount of gain from the power amplifier within the second frequency band.