A 74.0 dB-SNDR 175.4 dB-FoM Pipelined-SAR ADC Using a Cyclically Charged Floating Inverter Amplifier

Abstract

Energy and area efficiency are crucial performance indicators for small mobile IoT devices in terms of operating time and unit cost. Typically, mobile devices equipped with high-resolution sensors that operate in a range of a few megahertz of bandwidth require a pipelined-SAR ADC for digitizing analog signals [1]. However, a residue amplifier in the ADC needs to perform at a low noise level to achieve high resolution. This poses a deteriorated energy efficiency of the mobile devices since a substantial amount of energy is consumed in the residue amplifier to reduce thermal noise [1-4]. Recent floating inverter amplifiers (FIAs) [1], [4] in Fig. 1 (left) improve energy efficiency by utilizing the current-reuse technique.