Polar SiGe Class E and F Amplifiers Using Switch-Mode Supply Modulation

Abstract

Two integrated polar supply-modulated class E and F power amplifiers (PAs) in 0.18-mum SiGe BiCMOS process are presented. The amplifiers are used to transmit GSM-EDGE signals with an envelope dynamic range of 11 dB and a frequency range of 880-915 MHz. The amplifiers use switch-mode dc-dc buck converters for supply modulation, where sigma-delta (SigmaDeltaM), delta (DeltaM), and pulsewidth modulation are used to modulate the PA amplitude signal. A framework has been developed for comparing the three switching techniques for EDGE implementation. The measurement results show that DeltaM gives the highest efficiency and lowest adjacent channel power, providing class E and F PA efficiencies of 33% and 31%, respectively, at maximum EDGE output power. The corresponding class E and F linearized amplifiers' output spectra at 400-kHz offset are -54 and -57dBc, respectively