A 2.56-µs Dynamic Range, 31.25-ps Resolution 2-D Vernier Digital-to-Time Converter (DTC) for Cell-Monitoring

Capacitive sensor array (CSA) has emerged as a prominent approach in the field of biomedical detection, particularly for the analysis of cell morphology and the construction of a Cell-on-CMOS platform. To enhance overall sensitivity, this paper presents a novel 2-D vernier digital-to-time converter (2D V-DTC) with a resolution of 31.25 ps and a dynamic range of 2.56 µs. The 2-D vernier structure attains sufficient resolution while reducing the number of delay elements required, and seamlessly integrates with a counter-based controller, extending the dynamic range to effectively cover a significantly larger sensing window. The CSA biochip, fabricated in 180-nm CMOS technology, achieves results with an overall sensitivity of 880 code/fF. This achievement translates into an sensing resolution of 1.13 aF, demonstrating its potential to further advance the development of CMOS-based cell-monitoring platform.