Analysis of Reliability and Power Efficiency in Cascode Class-E PAs

Power efficiency in switched common source class-E amplifiers is usually obtained at the expense of device stress. Device stacking is a viable way to reduce voltage drops across a single device, improving long-term reliability. In this paper, we focus on cascode-based topologies, analyzing the loss mechanisms and giving direction to optimize the design. In particular, a new dissipative mechanism, peculiar of the cascode implementation, is identified and a circuit solution to minimize its effect is proposed. Prototypes, realized in a 0.13-mu m CMOS technology demonstrate 67% PAE while delivering 23 dBm peak power at 1.7 GHz. Good bandwidth was also realized with greater than 60% PAE over the frequency range of 1.4-2 GHz.