Clock distribution is central to digital technology and influences circuit performance, interconnect overhead and efficiency. However, ensuring reliable clock distribution across large digital systems with low skew and jitter—and in the presence of device variations and thermal noise—is a design challenge. Here we report a superconducting metamaterial resonant clock network that can provide energy-efficient power delivery to large superconducting digital systems. The resonant clock network is based on a metamaterial design with an infinite-wavelength zeroth-order resonance mode and utilizes the ultralow Joule loss of superconductors at microwave frequencies. With this approach, we perform S-parameter measurements for a 10 GHz design and validate a digital reciprocal quantum logic circuit with 48,000 junctions operating at 3.5 GHz. The network supports uniform power distribution with less than 1 dB variation across a 3 × 3 mm2 active chip area and around 30% power efficiency. Static power dissipation is 28 μW, which is similar to that of active devices.
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The data that support the findings of this study are available from the corresponding author upon reasonable request.
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We acknowledge the valuable conversation with O. Naaman regarding the clock network design. H. Dai and J. Egan assisted with the physical design of the clock network and functional circuits. J. Goodman and M. Lateef assisted with the microwave measurement. D. Harvey assisted with the circuit design. This research is based on the work supported in part by the ODNI, IARPA, via ARO, contract no. W911NF-14-C-0116. The views and conclusions contained herein are those of the authors and should not be interpreted as necessarily representing the official policies or endorsements, either expressed or implied, of the ODNI, IARPA, or the US Government.
All authors are or have been employed by Northrop Grumman Corp., which holds several patents relating to work discussed herein. See U.S. Patents 10,591,952; 10,884,450; 10,474,183; 10,461,867; 10,133,299; 9,722,589.
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Strong, J.A., Talanov, V.V., Nielsen, M.E. et al. A resonant metamaterial clock distribution network for superconducting logic. Nat Electron 5, 171–177 (2022). https://doi.org/10.1038/s41928-022-00729-7