2 unit switch consists of 59 logic gates and needs about 600 Josephson junctions without gate interconnections. We tested the gate-level circuit by logic simulation and found that it operates correctly at a throughput of 40 GHz." />


Logic Design of a Single-Flux-Quantum (SFQ) 22 Unit Switch for Banyan Networks

Yoshio KAMEDA  Shinichi YOROZU  Shuichi TAHARA  

Publication
IEICE TRANSACTIONS on Electronics   Vol.E85-C   No.3   pp.625-630
Publication Date: 2002/03/01
Online ISSN: 
DOI: 
Print ISSN: 0916-8516
Type of Manuscript: Special Section PAPER (Special Issue on Superconductive Electronics)
Category: Digital Devices and Their Applications
Keyword: 
single-flux-quantum circuit,  logic design,  cell-based design,  deep pipeline architecture,  packet switch,  

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Summary: 
We describe the logic design of a single-flux-quantum (SFQ) 22 unit switch. It is the main component of the SFQ Banyan packet switch we are developing that enables a switching capacity of over 1 Tbit/s. In this paper, we focus on the design of the controller in the unit switch. The controller does not have a simple "off-the-shelf" conventional circuit, like those used in shift registers or adders. To design such a complicated random logic circuit, we need to adopt a systematic top-down design approach. Using a graphical technique, we first obtained logic functions. Next, to use the deep pipeline architecture, we broke down the functions into one-level logic operations that can be executed within one clock cycle. Finally, we mapped the functions on to the physical circuits using pre-designed SFQ standard cells. The 22 unit switch consists of 59 logic gates and needs about 600 Josephson junctions without gate interconnections. We tested the gate-level circuit by logic simulation and found that it operates correctly at a throughput of 40 GHz.