High-Throughput Signal Component Separator for Asymmetric Multi-Level Outphasing Power Amplifiers

This paper presents an energy-efficient high-throughput and high-precision signal component separator (SCS) chip design for the asymmetric-multilevel-outphasing (AMO) power amplifier. It uses a fixed-point piece-wise linear functional approximation developed to improve the hardware efficiency of the outphasing signal processing functions. The chip is fabricated in 45 nm SOI CMOS process and the SCS consumes an active area of 1.5 mm
²
. The new algorithm enables the SCS to run at a throughput of 3.4 GSamples/s producing the phases with 12-bit accuracy. Compared to traditional low-throughput AMO SCS implementations, at 0.8 GSamples/s this design improves the area efficiency by 25× and the energy-efficiency by 2×. This fastest high-precision SCS to date enables a new class of high-throughput mm-wave and base station transmitters that can operate at high area, energy and spectral efficiency.