A 17ps time-to-digital converter implemented in 65nm FPGA technology

摘要

This paper presents a new architecture for time-to-digital conversion enabling a time resolution of 17ps over a range of 50ns with a conversion rate of 20MS/s. The proposed architecture, implemented in a 65nm FPGA system, consists of a pipelined interpolating time-to-digital converter (TDC). The TDC comprises a coarse time discriminator and a fine delay line, capable of sustained operation at a clock frequency of 300MHz. A Turbo version of the circuit implements a pipelined interpolating TDC with suppressed dead time to reach a conversion rate of 300MS/s at the expense of a systematic asymmetry that requires fast error correction. The TDCs proposed in this paper can be compensated for process, voltage, and temperature (PVT) variations using a conventional charge pump based feedback or a digital calibration technique. Results demonstrate the suitability of the approach for a variety of applications involving high-precision ultra-fast time discrimination, such as optical lifetime sensing, time-of-flight cameras, high throughput comlinks, RADARs, etc.