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Complementary Logic Circuit

IP.com Disclosure Number: IPCOM000083977D
Original Publication Date: 1975-Aug-01
Included in the Prior Art Database: 2005-Mar-01
Document File: 2 page(s) / 45K

Publishing Venue

IBM

Related People

Baechtold, W: AUTHOR [+2]

Abstract

A Josephson junction complementary logic circuit requires an asymmetry in the circuit, so that the state of the circuit will always be the same in the absence of a control current. To make the circuit monostable, an additional bias control current I-Co is applied to one of the equally sized pair of junctions J1, J2. However, no space consuming additional control line is needed, if the offset control current I-C0 is guided through one through one of the electrodes of Josephson junction J2 itself.

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Complementary Logic Circuit

A Josephson junction complementary logic circuit requires an asymmetry in the circuit, so that the state of the circuit will always be the same in the absence of a control current. To make the circuit monostable, an additional bias control current I-Co is applied to one of the equally sized pair of junctions J1, J2. However, no space consuming additional control line is needed, if the offset control current I-C0 is guided through one through one of the electrodes of Josephson junction J2 itself.

An implementation of an inverting gate is shown. Two Josephson junctions J1, J2 are connected in series between low-impedance voltage source +VG, R-S and ground. A compensating control current I-C1 + I-C2 provides tracking circuit properties. The input control current 1-C is fed via doubled control lines for enhancing the input signal. The offset control current I-C0 flows from the voltage source via resistor R-CO through the top electrode of junction J2 to ground. (This "control line is indicated by a dotted arrow in the upper left circuit diagram.)

A first fabrication step involves the resistors, i.e., source resistor R-S, offset control current resistor R-CO, and load resistor R-L1. The supply line is formed by a second metallization M2. Also the part forming the lower electrode of the junction pair J1, J2 and the output line is formed in the same M2 step.

After forming the junction layers, in a third metallization M3 step both upper junctio...