A 40-ps Resolution Robust Continuous Running VCRO-Based TDC for LiDAR Applications

This brief presents a robust continuous running voltage-controlled ring oscillator-based (VCRO-based) time to digital converter (TDC) for Light Detection and Ranging (LiDAR) applications. A robust two-counter method with a hybrid structure counter is proposed to avoid any sampling errors due to metastability and delay accumulation. To reduce the TDC dead time, a two-interleaved sampling channel is adopted. Compared to the prior methods, the proposed structure is free from sampling errors. The proposed TDC has been fabricated in 180-nm CMOS technology. Measurement results show that the error rate is negligible. The peak-to-peak INL and DNL are of 2.08 LSB and 0.46 LSB, respectively.