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Josephson shift registers

Journal Article · · Proceedings of the IEEE (Institute of Electrical and Electronics Engineers); (USA)
DOI:https://doi.org/10.1109/5.34125· OSTI ID:5523145
 [1]
  1. Westinghouse Electric Corp., Pittsburgh, PA (USA). Research and Development Center

This paper gives a review of Josephson shift register circuits that were designed, fabricated, or tested, with emphasis on work in the 1980s. Operating speed is most important, since it often limits system performance. Older designs used square-wave clocks, but most modern designs use offset sine waves, with either two or three phases. Operating margins and gate bias uniformity are key concerns. The fastest measured Josephson shift register operated at 2.3 GHz, which compares well with a GaAs shift register that consumes 250 times more power. The difficulties of high-speed testing have prevented many Josephson shift registers from being operated at their highest speeds. Computer simulations suggest that 30-GHz operation is possible with current Nb/Al/sub 2/O/sub 3//Nb technology. Junctions with critical current densities near 10 kA/cm/sup 2/ would make 100-GHz shift registers feasible.

OSTI ID:
5523145
Journal Information:
Proceedings of the IEEE (Institute of Electrical and Electronics Engineers); (USA), Journal Name: Proceedings of the IEEE (Institute of Electrical and Electronics Engineers); (USA) Vol. 77:8; ISSN IEEPA; ISSN 0018-9219
Country of Publication:
United States
Language:
English