A fully differential, 200MHz, programmable gain, level-shifting, hybrid amplifier/power combiner/test buffer, using pre-distortion for enhanced linearity

Abstract

With the continuous advancement of standards in high-end telecommunication systems, requirements for analog circuitry have become ever more demanding. The new standards not only want to support better modulation schemes, demanding less noise with higher linearity, but also require increased bandwidth from analog circuitry. This paper describes a fully differential, programmable gain, baseband power combiner with a bandwidth of 200MHz, using pre-distortion for extra linearity, that offers also level-shifting and test buffer functionalities. The pre-distortion allows the improvement of linearity in the amplifiers AB stage, what otherwise would be a limiting factor in rail-to-rail swing operations and lowering the maximum throughput.