109.9-dB DR and 17.9-Bit ENOB Dynamic Zoom CDC Design for Audio Applications

Capacitive sensors are one of the most widely used sensors today. In recent years, High resolution has assumed a paramount role in sensor design, guaranteeing precise measurement outcomes. Quantification to the aF level is urgently needed. This paper presents the first dynamic Zoom capacitance to digital converter (CDC) incorporating noise coupling (NC) technology, which is intended for high-precision sensor applications in the audio domain. The proposed dynamic CDC is a hybrid of a high-resolution
$\mathbf{\Delta}\mathbf{\Sigma}$
modulator
$(\mathbf{\Delta}\mathbf{\Sigma}\mathbf{M})$
and a high-efficiency SAR-based CDC to achieve better performance. It is implemented in the TSMC 180 nm process, and the simulation results show that it achieves 109.9dB DR and 109.3dB SNR within the bandwidth of 20kHz, consuming
$\mathbf{81}\boldsymbol{\mu}\mathbf{W}$
from a 1.2V supply. These advancements are accomplished through the combined utilization of coarse and fine conversions, noise coupling techniques, SAR-assisted multi-bit quantizers, and operational transconductance amplifiers (OTAs) based on dynamic bias inverters.