An IC for linearizing RF power amplifiers using envelope elimination and restoration

Efficient power amplifiers (PAs) are desirable because power amplifiers typically dominate the power consumed in portable radio devices. Cellular systems such as the advanced mobile phone system (AMPS) employ modulation schemes that generate constant amplitude RF outputs to use efficient but nonlinear PAs. Modern digital communication standards such as the North American dual-mode cellular (NADC) system require nonconstant amplitude RF outputs to maximize frequency spectral usage, and therefore require linear PAs. The traditional approach to linear RF power amplification is to back-off the output power of a PA until its distortion is reduced to an acceptable level. Power back-off can lead to significant reduction in output power and efficiency. The envelope elimination and restoration (EER) system is an alternative to power back-off, to simultaneously achieve efficiency and linearity in RF PAs.