New Rsfq Circuits

Several new circuits of the Rapid Single-Flux-Quantum (RSFQ) family of Josephson-j unction digital devices [1] have been designed, fabricated using a 2.5-nm lOOO-A/cm2 niobium trilayer technology, and tested at low frequencies. Numerical simulation and measurements have shown that these new circuits have considerably wider parameter margins, due to application of several new design methods. We have also carried out an experiment on measurement of the rate of errors in a simple RSFQ circuit including an inverter, confluence buffer, and Josephson transmission line. Near the middle of the parameter window at 4.2K, the error probability was definitely lower than 3xlO-15 per logic operation, despite experimentation with rudimentary shielding and filtering.