1. Analysis and Stabilization of Signal Reflections in Gate-to-Gate Connections for AQFP Circuits
- Author
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Michael A. Johnston, Christopher L. Ayala, Tomoyuki Tanaka, and Nobuyuki Yoshikawa
- Subjects
Junctions ,Standards ,matching network ,Reflection ,maximum propagation delay ,large-scale superconductor circuits ,AQFP circuits ,superconducting logic circuits ,Adiabatic logic ,integrated circuit interconnections ,energy analysis ,interconnection modelling ,quantum flux parametron (QFP) ,impedance matching network ,Electrical and Electronic Engineering ,microwave circuits ,transmission line effects ,signal reflections ,lossless transmission line model ,resistance 8 ohm ,impedance matching ,signal integrity ,transmission lines ,standard buffer gate ,Impedance ,time 6.1 ps ,Logic gates ,transmission line ,microwave circuit theory ,data signals ,Condensed Matter Physics ,conventional digital logic circuits ,transmitted data ,frequency content ,stabilization ,Electronic, Optical and Magnetic Materials ,gate-to-gate connections ,size 3.0 mm ,data signal integrity ,Power transmission lines ,timing characteristics ,integrated circuit modelling - Abstract
Signal integrity of transmitted data is critical for achieving highly dense, large-scale superconductor circuits. Transmission line effects, such as signal reflections, are investigated and concepts from microwave circuit theory and conventional digital logic circuits are applied to AQFP circuits. The lossless transmission line model is used for interconnection modelling. The frequency content and timing characteristics of data signals are used to analytically predict a maximum propagation delay of 6.1 ps before failure due to reflections. This coincides well with our own results, and with those obtained in a separate study using simulation techniques. The investigation then extends towards the design of an impedance matching network with the aim of reducing reflections. The input impedance of a standard buffer gate is derived, and then matched to an 8 Ω transmission line. The proposed impedance matching network maintains data signal integrity up to 3 millimetres. Energy analysis of the matching network is also performed and a 36 % increase in length for similar energy consumption is achieved over alternative solutions.
- Published
- 2023
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