Abstract
This paper presents a precise time-difference repetition technique to enhance the timing accuracy in repetition based time-to-digital converters (TDC). In the proposed scheme, any delay mismatches during timing difference repetition process can be removed. The proposed circuit could be used for multi-step TDC, delta-sigma TDC, and SAR-type TDC. The proposed scheme was designed and simulated with a 65-nm CMOS process. The proposed circuit shows a delay variation of about 100fs in the presence of device mismatches, which is much less than that of conventional approaches. The input time range and the conversion rate is 480ps and 100Msps if applied to a 2-step TDC, respectively.
