Comparisons of Metastability Impact in Time-Domain and Asynchronous SAR ADCs for Serial I/O Receivers

This paper develops metastability error models for Time-Domain Analog-to-Digital Converters (TD ADCs) by analyzing the input-to-output delay of the time comparator (TCMP) and deriving the error probability. Additionally, this paper presents an analysis of the impact of metastability error propagation on the ADC-based 112 Gb/s PAM-4 link, with a comparative study of the TD ADC and asynchronous SAR (ASAR) ADC. Simulation results demonstrate that the TD ADC is particularly suited for high-speed and low supply voltage applications.