Interconnect Routing for Large-Scale RSFQ Circuits

Jabbari, Tahereh; Krylov, Gleb; Whiteley, S.R.; Mlinar, Eric; Kawa, Jamil; Friedman, Eby G.

doi:10.1109/tasc.2019.2903023

Cited by 74 publications

(8 citation statements)

References 20 publications

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“…However, the utilization of passive transmission lines (PTLs) looks more promising for long-range connections. It is shown that PTLs are suitable for high-density routing with low cross talk, allowing fast data transfer and precision-timing design of the circuits [48,49]. The cells can even be connected through PTLs only, although, with a relatively large width of PTLs, this option poses certain limitations on the integration density.…”

Section: Discussionmentioning

confidence: 99%

Superconducting Circuits without Inductors Based on Bistable Josephson Junctions

et al. 2021

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Magnetic flux quantization in superconductors allows the implementation of fast and energy-efficient digital superconducting circuits. However, information representation in magnetic flux severely limits the functional density and is a long-standing problem. Here, we introduce the concept of superconducting digital circuits that do not utilize magnetic flux and have no inductors. We argue that neither the use of geometric nor kinetic inductance is promising for the scaling down of superconducting circuits. The key idea of our approach is the utilization of bistable Josephson junctions, allowing the representation of information through the Josephson energy. Since the proposed circuits are composed only of Josephson junctions, they can be called all-Josephson junction (all-JJ) circuits. We present a methodology for the design of circuits consisting of conventional and bistable junctions. We analyze the principles of the circuit's functioning, ranging from simple logic cells to an 8-bit parallel adder. The utilization of bistable junctions in the all-JJ circuits is promising for the simplification of schematics and a decrease of the JJ count, leading to space efficiency.

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Section: Discussionmentioning

confidence: 99%

Superconducting Circuits without Inductors Based on Bistable Josephson Junctions

et al. 2021

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“…The number of JTLs depends upon the distance between the SFQ cells. The length of one JTL stage is approximately 20 m [7] (in a 10 kA/cm 2 technology). For example, for a distance of 200 m between SFQ cells, ten JTLs are required.…”

Section: Josephson Transmission Linesmentioning

confidence: 99%

“…Although not a significant issue in current MSI SFQ circuits, the greater area, power, and delay of a JTL are a significant challenge for prospective VLSI complexity SFQ circuits. Furthermore, certain constraints exist on the inductance within a JTL cell, which reduces the design flexibility of the physical layout [7,8,[36][37][38].…”

Section: Josephson Transmission Linesmentioning

confidence: 99%

“…An important characteristic of SFQ circuits is absolute zero DC resistance interconnects [6]. SFQ circuits utilize two distinct types of interconnect -active Josephson transmission lines (JTL) and passive transmission lines (PTL), composed of a microstrip or stripline with a matched driver and receiver [7][8][9]. A comparison of the energy dissipated by interconnects for CMOS and SFQ is shown in Fig.…”

mentioning

confidence: 99%

“…The resonance in PTLs is dependent on the length of the PTL segment and the frequency of the SFQ signal. Specialized algorithms and guidelines for SFQ-based automated routing tools are needed to assign the interconnect length for each line and driver/receiver configuration when propagating a signal along a long passive interconnect [7,[20][21][22][23][24].…”

mentioning

confidence: 99%

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