Ramon A. Gomez

A 10-to-650MHz 1.35W class-AB power amplifier with instantaneous supply-switching efficiency enhancement

A broadband PA is presented, combining a Class AB core with instantaneous supply-switching (ISS). High-ft NPN cascodes switch the amplifier signal current to high or low supply rails depending on instantaneous amplitude. Current-mode switching at GHz rates enhances efficiency for bandwidths well beyond existing envelope trackers. 1.35W peak power and efficiency=13.6% @11dB PAPR are observed. The combination of Pout, large fractional bandwidth and high-PAPR efficiency exceeds prior art.

Training of digital predistortion based on signal-to-distortion-ratio measurements

A novel training technique for digital predistortion (DPD) systems is presented. Previous techniques rely on the time-domain (TD) difference between the ideal transmitter input and the distorted amplifier output as an error metric. This work presents DPD training based solely on frequency-domain signal-to-distortion-ratio (SDR) information. The only a priori information required is the spectral occupancy of the desired signal. The approach is applied to a broadband SiGe BiCMOS power amplifier, including measured results.