A Systematic Design Method for Direct Delta-Sigma Receivers

Abstract

Next generation receivers, such as the direct ΔΣ receiver (DDSR), shift the boundary between analog and digital closer to the antenna by merging the functionalities of different sub-blocks. In the DDSR, the analog components are used to their maximum potential as each stage participates in amplification, blocker filtering, anti-aliasing, and quantization noise shaping simultaneously, resulting in a compact design. To overcome the increased design complexity, the implemented DDSRs rely on common practices in receiver and ΔΣ modulator design. In this paper, we will show that the common design practices for neither receivers nor ΔΣ modulators yield optimal performance for the DDSR, and propose a systematic design method for gmC based DDSRs. The method enables improved performance and a straight-forward design flow by combining the gain partitioning, noise considerations, and loop-filter design. The developed method is demonstrated by designing a gmC based DDSR using a 28 nm FDSOI CMOS process. Simulations of the DDSR indicate state-of-the-art performance.