Accurate Time-to-Digital Converter Based on Xilinx's Digital Clock Managers

This paper presents an accurate and simple delay measurement method based on Xilinx's Digital Clock Managers. Particularly, variable phase shift is the modules' capability exploited in our approach. This method enables the implementation of a time-to-digital converter that achieves a resolution of 200ps on a Xilinx's Virtex or Spartan-3 FPGA without requiring manual placement & routing, nor an external calibration process. This circuit can be used in any application that demands a precise measurement of a static delay.