Towards minimum power analog filters

摘要

This paper investigates the improvement margins in term of energy efficiency of analog filters. Starting from a landscape of analog filters presented at ISSCC until 2012, energy limits for most common analog filters architectures (Gm-C and Active-RC) are traced. Active-RC filters with reduced bandwidth requirements have larger margins of improvements compared to Gm-C. Technology scaling impact is also evaluated. Supply reduction that join the technology scaling seems to have a limited effect on Gm-C filters, as their energy limit depends on the SNR only. However, technology scaling enables larger bandwidth opamps, pushing the Active-RC technique at higher and higher frequency, where Gm-C approach generally dominates. Results have been confirmed by the detailed analysis of two of the most performing analog filters from literature.