NbN-BASED DIGITAL-TO-ANALOG CONVERTERS FOR A PROGRAMMABLE JOSEPHSON VOLTAGE STANDARD

摘要

Two kinds of digital-to-analog converters (DACs) for a programmable Josephson voltage standard have been fabricated using NbN/TiN/NbN junctions. One is 8-bit DACs containing 32 768 junctions each. The other is 11-bit DACs containing 327 680 junctions each. The former has ability of generating 1 V-output voltages and the latter 10 V-output voltages. Both devices have been operated with a compact cryocooler.