Digital SQUID based on DROS with flux locked loop circuit consisting of 4JL up/down counter and R-2R ladder-type D/A converter

摘要

We have designed a digital SQUID based on a double relaxation oscillation SQUID (DROS) with a flux locked loop (FLL) circuit consisting of an Up/Down counter and a D/A converter. The Up/Down counter was designed using 4JL gates operated with 2-phase power system. The D/A converter was designed using the R-2R ladder-type D/A converter. We simulated dynamic behavior of a DROS with a FLL circuit combined with the Up/Down counter and the D/A converter. Simulation results showed correct flux locked behavior and large slew rate of 10{sup}7Φ{sub}0/s for the digital SQUID.