Abstract
The increasing complexity of modern rapid single flux quantum (RSFQ) circuits has made on-chip signal routing an issue of growing importance. In this chapter, several methods for routing large-scale RSFQ circuits are described, and a process is presented for determining when to use passive microstrip transmission lines (PTL) and active Josephson transmission lines (JTL). The effect of the size of the JTL inductor and Josephson junctions on the length of a JTL chain for a target delay is also discussed. The dependence of the JTL inductance on the physical layout is evaluated, and the effects of the primary PTL parameters on delay are characterized. A novel PTL driver and receiver configuration is also proposed. Trade-offs among the number of JJs, inductance, and length of a PTL stripline in the receiver and driver circuits are reported. The energy dissipation is evaluated for two different interconnects. A trade-off between the PTL circuits and an optimized JTL in terms of energy dissipation and delay is discussed. Guidelines for choosing the optimal element values are determined, and a simulated bias margin of \(\pm 29\%\) for the bias current of the receiver operating at 20 GHz in a 10 kA/cm\({ }^2\) technology for a 1 mm transmission line is achieved. Summarizing, guidelines and design trade-offs appropriate for automated layout and synthesis are provided for driving long interconnect in SFQ VLSI circuits.
Access this chapter
Tax calculation will be finalised at checkout
Purchases are for personal use only
References
T. Jabbari, F. Shanehsazzadeh, H. Zandi, M. Banzet, J. Schubert, M. Fardmanesh, Effects of the design parameters on characteristics of the inductances and JJs in HTS RSFQ circuits. IEEE Trans. Appl. Supercond. 28(7), 1–4 (2018)
T. Jabbari, G. Krylov, S. Whiteley, E. Mlinar, J Kawa, E.G. Friedman, Interconnect routing for large scale RSFQ circuits. IEEE Trans. Appl. Supercond. 29(5), 1102805 (2019)
T. Jabbari, E.G. Friedman, Global interconnects in VLSI complexity single flux quantum systems, in Proceedings of the Workshop on System-Level Interconnect: Problems and Pathfinding Workshop (2020), pp. 1–7
T. Jabbari, G. Krylov, S. Whiteley, J. Kawa, E.G. Friedman, Repeater insertion in SFQ interconnect. IEEE Trans. Appl. Supercond. 30(8), 5400508 (2020)
T. Jabbari, E.G. Friedman, Transmission lines in VLSI complexity single flux quantum systems, in Proceedings of the PhotonIcs and Electromagnetics Research Symposium (2023), pp. 1749–1759
R. Bairamkulov, T. Jabbari, E.G. Friedman, QuCTS – single flux quantum clock tree synthesis. IEEE Trans. Comput. Aided Des. Integr. Circuits Syst. 41(10), 3346–3358 (2022)
T. Jabbari, G. Krylov, S. Whiteley, J. Kawa, E.G. Friedman, Resonance effects in single flux quantum interconnect, in Proceedings of the Government Microcircuit Applications and Critical Technology Conference (2020), pp. 1–5
T. Jabbari, E.G. Friedman, Surface inductance of superconductive striplines. IEEE Trans. Circuits Syst. II Express Briefs 69(6), 2952–2956 (2022)
S.K. Tolpygo, V. Bolkhovsky, T.J. Weir, A. Wynn, D.E. Oates, L.M. Johnson, M.A. Gouker, Advanced fabrication processes for superconducting very large-scale integrated circuits. IEEE Trans. Appl. Supercond. 26(3), 1–10 (2016)
T. Van Duzer, C.W. Turner, Principles of Superconductive Devices and Circuits, 2nd edn. (Prentice Hall, Hoboken, 1999)
A. Fujimaki, M. Tanaka, T. Yamada, Y. Yamanashi, H. Park, N. Yoshikawa, Bit-serial single flux quantum microprocessor CORE. IEICE Trans. Electron. 91(3), 342–349 (2008)
Y. Hashimoto, S. Yorozu, Y. Kameda, A. Fujimaki, H. Terai, N. Yoshikawa, Design and investigation of gate-to-gate passive interconnections for SFQ logic circuits. IEEE Trans. Appl. Supercond. 15(3), 3814–3820 (2005)
H. Suzuki, S. Nagasawa, K. Miyahara, Y. Enomoto, Characteristics of driver and receiver circuits with a passive transmission line in RSFQ circuits. IEEE Trans. Appl. Supercond. 10(3), 1637–1641 (2000)
S. Razmkhah, A. Bozbey, Design of the passive transmission lines for different stripline widths and impedances. IEEE Trans. Appl. Supercond. 26(8), 1–6 (2016)
D.K. Brock, RSFQ technology: circuits and systems. Int. J. High Speed Electron. Syst. 11(1), 307–362 (2001)
Y. Kameda, S. Yorozu, Y. Hashimoto, A new design methodology for single-flux-quantum (SFQ) logic circuits using passive-transmission-line (PTL) wiring. IEEE Trans. Appl. Supercond. 17(2), 508–511 (2007)
S.K. Tolpygo, V. Bolkhovsky, T.J. Weir, C.J. Galbraith, L.M. Johnson, M.A. Gouker, V.K. Semenov, Inductance of circuit structures for MIT LL superconductor electronics fabrication process with 8 niobium layers. IEEE Trans. Appl. Supercond. 25(3), 1–5 (2015)
K. Gaj, Q.P. Herr, V. Adler, A. Krasniewski, E.G. Friedman, M.J. Feldman, Tools for the computer-aided design of multigigahertz superconducting digital circuits. IEEE Trans. Appl. Supercond. 9(1), 18–38 (1999)
C.J. Fourie, Digital superconducting electronics design tools - status and roadmap. IEEE Trans. Appl. Supercond. 28(5), 1–12 (2018)
S.K. Tolpygo, E.B. Golden, T.J. Weir, V. Bolkhovsky, Inductance of superconductor integrated circuit features with sizes down to 120 nm. Supercond. Sci. Technol. 34(8), 1–24 (2021)
Y.I. Ismail, E.G. Friedman, J.L. Neves, Repeater insertion in tree structured inductive interconnect. IEEE Trans. Circuits Syst. II Analog Digital Signal Process. 48(5), 471–481 (2001)
H. Engseth, S. Intiso, M.R. Rafique, E. Tolkacheva, A. Kidiyarova-Shevchenko, A high frequency test bench for rapid single-flux-quantum circuits. Supercond. Sci. Technol. 19(5), S376–S380 (2006)
Y. Yamanashi, M. Tanaka, A. Akimoto, H. Park, Y. Kamiya, N. Irie, N. Yoshikawa, A. Fujimaki, H. Terai, Y. Hashimoto, Design and implementation of a pipelined bit-serial SFQ microprocessor, CORE1\(\beta \). IEEE Trans. Appl. Supercond. 17(2), 474–477 (2007)
Y. Hashimoto, S. Nagasawa, T. Satoh, K. Hinode, H. Suzuki, T. Miyazaki, M. Hidaka, N. Yoshikawa, H. Terai, A. Fujimaki, Superconductive single-flux-quantum circuit/system technology and 40 Gb/s switch system demonstration, in Proceedings of the IEEE International Solid-State Circuits Conference (2008), pp. 532–533
K. Nakamiya, N. Yoshikawa, A. Fujimaki, H. Terai, Y. Hashimoto, Direct measurements of propagation delay of single-flux-quantum circuits by time-to-digital converters. IEICE Electron. Express 5(9), 332–337 (2008)
D.T. Yohannes, A. Inamdar, S.K. Tolpygo, Multi-J\({ }_c\) (Josephson critical current density) process for superconductor integrated circuits. IEEE Trans. Appl. Supercond. 19(3), 149–153 (2009)
Y. Hashimoto, S. Yorozu, Y. Kameda, V.K. Semenov, A design approach to passive interconnects for single flux quantum logic circuits. IEEE Trans. Appl. Supercond. 13(2), 535–538 (2003)
M. Tanaka et al., Demonstration of a single-flux-quantum microprocessor using passive transmission lines. IEEE Trans. Appl. Supercond. 15(2), 400–404 (2005)
V. Adler, E.G. Friedman, Uniform repeater insertion in RC trees. IEEE Trans. Circuits Syst. I: Fundam. Theory Appl. 47(10), 1515–1523 (2000)
A. Shukla, D. Kirichenko, A. Sahu, B. Chonigman, A. Inamdar, Investigation of passive transmission lines for the MIT-LL SFQ5EE process. IEEE Trans. Appl. Supercond. 29(5), 1–7 (2019)
Author information
Authors and Affiliations
Corresponding authors
Rights and permissions
Copyright information
© 2024 The Author(s), under exclusive license to Springer Nature Switzerland AG
About this chapter
Cite this chapter
Krylov, G., Jabbari, T., Friedman, E.G. (2024). Interconnect Routing for Large-Scale SFQ Circuits. In: Single Flux Quantum Integrated Circuit Design. Springer, Cham. https://doi.org/10.1007/978-3-031-47475-0_23
Download citation
DOI: https://doi.org/10.1007/978-3-031-47475-0_23
Published:
Publisher Name: Springer, Cham
Print ISBN: 978-3-031-47474-3
Online ISBN: 978-3-031-47475-0
eBook Packages: EngineeringEngineering (R0)