New SQUID gate and its implementation into logic circuits

We propose non-latching gates based on Superconducting QUantum Interference Device (SQUID) and logic circuits based on it. The gate consists of a 3-junction-SQUID coupled with an RF-SQUID inductively. According to numerical simulation, the wide bias margin reached /spl plusmn/52%. Adopting the magnetic coupling to apply input signals, the fan-out larger than unity was obtained without reducing signal current level. These consequences enabled us to realize complicated logic functions using this gate, The gate delay was 4.5ps at Jc=10kA/cm/sup 2/. An EXOR gate composed of two gates had the bias margin of /spl plusmn/35% and the delay time of 12ps. The operation in non-latching mode is also suitable for digital circuits based on HTS junctions.