Synchronizer-Free Digital Link Controller

Johannes Bund, Matthias Fugger, Christoph Lenzen, Moti Medina

Research output: Contribution to journalArticlepeer-review

1 Scopus citations


This work presents a producer-consumer link between two independent clock domains. The link allows for metastability-free, low-latency, high-throughput communication by slight adjustments to the clock frequencies of the producer and consumer domains steered by a controller circuit. Any such controller cannot deterministically avoid, detect, nor resolve metastability. Typically, this is addressed by synchronizers, incurring a larger dead time in the control loop. We follow the approach of Friedrichs et al. (TC 2018) who proposed metastability-containing circuits. The result is a simple control circuit that may become metastable, yet deterministically avoids buffer underrun or overflow. More specifically, the controller output may become metastable, but this may only affect oscillator speeds within specific bounds. In contrast, communication is guaranteed to remain metastability-free. We formally prove correctness of the producer-consumer link and a possible implementation that has only small overhead. With SPICE simulations of the proposed implementation we further substantiate our claims. The simulation uses 65nm process running at roughly 2GHz.

Original languageEnglish
Article number9085899
Pages (from-to)3562-3573
Number of pages12
JournalIEEE Transactions on Circuits and Systems I: Regular Papers
Issue number10
StatePublished - Oct 2020
Externally publishedYes

Bibliographical note

Publisher Copyright:
© 2004-2012 IEEE.


Manuscript received October 23, 2019; revised March 2, 2020 and April 19, 2020; accepted April 19, 2020. Date of publication May 4, 2020; date of current version October 5, 2020. The work of Johannes Bund and Christoph Lenzen was supported by the European Research Council (ERC) under the European Union’s Horizon 2020 Research and Innovation Programme under Grant 716562. The work of Matthias Függer was supported by DigiCosme and DEPEC MODE. The work of Moti Medina was supported in part by the Israel Science Foundation under Grant 867/19. This article was recommended by Associate Editor A. Elwakil. (Corresponding author: Johannes Bund.) Johannes Bund is with the Max Planck Institute for Informatics, Saarland Informatics Campus, 66123 Saarbrücken, Germany, and also with the Saar-brücken Graduate School of Computer Science, 66123 Saarbrücken, Germany (e-mail: [email protected]).

FundersFunder number
Horizon 2020 Framework Programme716562
European Research Council
Israel Science Foundation867/19


    • Producer-consumer link
    • continuous processes
    • digital controllers
    • metastability-containing mixed signal control loop
    • metastability-free


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