A high-precision coarse-fine time-to-digital converter with the analog-digital hybrid interpolation

Abstract

An innovative high-precision coarse-fine time-to-digital converter (TDC) is presented. The TDC architecture mainly consists of a coarse counter and a delay-line-based analog-digital hybrid interpolator. In order to improve the precision, the key timing control of the interpolator is provided by a novel customized synchronizer. Comparing to the traditional delay-line-based interpolator, the proposed analog-digital hybrid interpolator using the multi-voltage sampling technique improves the resolution significantly. A prototype chip has been fabricated in a 0.35 µm CMOS process. After the calibration and calculation based on fitting algorithms, the TDC prototype reaches a dynamic range of 512 ns and a single-channel single-shot precision of 6 ps using the external look-up table (LUT) for the interpolator.