A DC-POWERED JOSEPHSON LOGIC FAMILY THAT USES HYBRID UNLATCHING FLIP-FLOP LOGIC ELEMENTS (HUFFLES)

This paper describes the development of a dc-powered Josephson logic f amily that uses hybrid unlatching flip-flop logic elements (Huffles), The Huffle circuit used in this study is modified by adding a parallel resistor to the original Hebard-type Huffle circuit. Analysis of the circuit's operation shows that the undesirable hung-up phenomena are p revented by this modification, Based on the result of the analysis, th e circuit's parameters are derived and a typical operating margin of /-26% is obtained, Besides AND/OR operations using a threshold logic o peration, two-input exclusive OR (XOR), two-input multiplexor (MUX), a nd three-input majority (MAJ) operations are realized using a Huffle g ate in which 2-Josephson-interferometers (2JI) in the standard Huffle gate are replaced by stacked-2JI's, Thus, a Huffle logic family, forme d from NOT, AND, OR, XOR, MUX, MAJ, and flip-flop (FF), are constructe d, By using this Huffle logic family, a 6-b arithmetic logic operating unit (ALU), a 6-b analog-to-digital converter (ADC), and a 6-b gray-t o-binary converter (GBC) have been successfully operated, During highs peed testing, a 1-b comparator was operated up to an input bandwidth o f 6 GHz.