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Josephson Digital and Analog Devices with Niobium Junctions

  • S. Hasuo
Conference paper

Abstract

This paper describes recent progress on digital and analog circuits using all niobium (Nb/AlQx/Nb) Josephson junctions. A niobium junction has excellent characteristics with a low leakage current, and is stable with respect to thermal cycling and long term storage. We used the niobium junctions in a variety of digital and analog circuits. This paper firstly describes the logic gate family, named the MVTL (Modified Variable Threshold Logic) gate family. The lowest experimentally obtained MVTL-OR gate delay was only 2.5 ps with a power consumption of 17 uW/gate. The gate family was applied to various circuits, such as 8-bit shift registers, 16-bit ALUs (Arithmetic Logic Unit), and 4-bit microprocessors. We confirmed the high speed operation of less than 10 ps per gate on the average for these circuits.

We also developed a new high-sensitivity magnetic sensor using the SQUID (Superconducting Quantum Interference Device). We call it a single-chip SQUID magnetometer, because the feedback circuit, which is operated at room temperature in a conventional SQUID system, has been integrated on the same chip as the SQUID sensor itself.

Keywords

Critical Path Josephson Junction Analog Circuit Pickup Coil Gate Delay 
These keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.

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Copyright information

© Springer Japan 1989

Authors and Affiliations

  • S. Hasuo
    • 1
  1. 1.Fujitsu Laboratories Ltd.Atsugi, Fujitsu LimitedAtsugi, 243-01Japan

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