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Three Junction Injection Device with Symmetric and Asymmetric Injection

IP.com Disclosure Number: IPCOM000044959D
Original Publication Date: 1983-Jan-01
Included in the Prior Art Database: 2005-Feb-06
Document File: 2 page(s) / 51K

Publishing Venue

IBM

Related People

Anderson, CJ: AUTHOR

Abstract

Current injection devices need inductance compensation if the variations in junction critical currents and inductances are too large. Two of inductance compensation are: 1) trimming the inductance during fabrication, and 2) using Josephson junctions as inductors.

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Three Junction Injection Device with Symmetric and Asymmetric Injection

Current injection devices need inductance compensation if the variations in junction critical currents and inductances are too large. Two of inductance compensation are: 1) trimming the inductance during fabrication, and 2) using Josephson junctions as inductors.

Fig. 1 shows a new device that makes use of Josephson junctions as inductors. If the total inductance L(C) is equal to L(B)/2, and L(A) is equal to L(B), the device would be the same as a 1-3 two-junction current injection device (CID). By making L(C) greater than L(B)/2, the I(mo) of the device is lowered and the threshold curve is reduced, where I(CS) is the symmetrically injected current and I(CA) is the asymmetrically injected current.

Fig. 2 shows two isolation devices feeding a CID. Currents which the isolation devices inject into the CID can be estimated from the electrical diagram in Fig. 3, where R(j) is the leakage resistance of the isolator junctions and V is the power supply voltage.

The ratio (see Fig. 1) of L(C) to L(B) can be set such that the operating window of the CID is optimized with respect to the output currents of the isolation devices. If the average I(O) of the chip varies from chip to chip and the supply resistor R(S) has to be trimmed, the currents the isolation devices inject into the CID will be a function of the average I(O) for the chip.

Fig. 3 is an equivalent circuit to Fig. 2 with a 6 mV power supply...