A 118.6fJ/Conversion-Step Two-Step Time-Domain RC-to-Digital Converter With 33nF/10MΩ Range and 53aFrms Resolution

• DOI: 10.1109/a-sscc56115.2022.9980735
• Publication Date: 2022-12-19T20:09:13Z
• Authors: Hoyong Seong; Chongsoo Jung; Donghyun Youn; Junghyup Lee; Sohmyung Ha; Minkyu Je
• Keywords: Oversampling; Delta-sigma modulation

Sensor readout ICs for internet-of-things (IoT) systems require not only high energy efficiency and resolution but also a wide input range to cover variety of sensors with different output types characteristics [1], [2]. Readout methods based on delta-sigma modulation (DSM) [3], [4] two-step conversion (successive approximation + time-domain (TD) DSM) [5] have been proposed achieve efficiency, these structures suffer from limited ranges as they convert the sensor voltage, whose is strictly constrained by given supply rails. Alternatively, TD method converts into signal, eliminating constraint [2], [6]. However, its jitter performance oscillator counting clock [1]. This issue can be addressed together dual-oscillator-based structure utilizing large oversampling ratio (OSR) power-hungry high-frequency reference (R-OSC) should continuously operate reduce quantization noise (Q-noise), degrading greatly. Although this both Q-noise random sacrificing time, signal-to-noise (SNR) per itself. Here, we present 2-stepconversion IC achieving range, resolution, altogether.