28.2 A 189.3dB-FoMs 14.5fJ/Conversion-Step Continuous-Time Noise-Shaping SAR Capacitance-to-Digital Converter

In recent years, capacitance-to-digital converters (CDCs) have attracted significant attention in IoT applications to monitor environmental conditions such as humidity [1]–[3] and pressure [3]–[5]. One of the key challenges is how accurately they can measure small capacitance variations caused by changes in dielectric properties at lower power consumption, increasing the demand for power-efficient high-resolution CDCs. Among various topologies, the $\Delta\Sigma \mathrm{M}$ -based structure has emerged as a preferred choice for its ability to achieve high resolution by oversampling and noise-shaping. However, its capacitance-resolution performance is still limited by the $\text{kT}/\mathrm{C}$ and flicker noises.