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IEEE Transactions on Applied Superconductivity

Quantum flux parametron: a single quantum flux device for Josephson supercomputer

M. Hosoya, W. Hioe, Juan Casas, R. Kamikawai, Y. Harada, Yasuo Wada, H. Nakane, Reiji Suda, Eiichi Goto

Published Jun 1, 1991• 149 citations
Publisher

Abstract

A quantum flux parametron (QFP), a single quantum flux superconductive device that has a potential of up to 100-GHz switching with nW-order power dissipation, is considered. The potential of the QFP and key technologies when QFPs are applied to a Josephson supercomputer are described. Switching speed, stability, and power dissipation of a QFP are discussed. QFP gates, circuits, and systems are next described. Then, ultra-fast clock distribution using a standing wave is explained. High-speed operation at more than 10 GHz and 10/sup 14/ error-free operations per QFP have been demonstrated. Finally described is a high-density packaging scheme by three-dimensional integration, which is very important for ultra-high speed circuits because the propagation delay becomes dominant in such circuits.>

DOI
10.1109/77.84613

Related papers

Quantum Flux Parametron

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This book concerns a Josephson device for supercomputers which has extremely low heat dissipation (about 106 times less than semiconductor devices and 103 times less than voltage-based Josephson devices). In the previous book on Quantum Flux Parametrons (QFPs), DC Flux Parametron, the basic device operation are described. This book deals in much greater depth on the problems which are faced by the QFP. The device characteristics are worked out in detail showing clearly the analysis methods used. A new logic gate using the QFP is described with respect to its basic scheme, operation, and ways for forming logic circuits. The problems faced by the basic QFP are much reduced in the new logic gate. As the QFP operates near the Heisenberg and Boltzmann limits for computing devices, we also show the relationship between speed and stability. The book contains the latest analytical results on QFPs.The material presented in the book can be understood with very little mathematical training or knowledge about superconducting physics. It is also self-contained and does not require reading of other material. Most of the device characteristics can be reproduced from the equations given using simple programs. A circuit simulator is not needed except for high speeds when transient behavior becomes important.

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A study on circuits to improve the margin of the quantum flux parametron

W. Hioe, M. Hosoya, Eiichi Goto

The quantum-flux parametron (QFP) is a single-flux quantum Josephson device with a high gain of over 20 dB and a low power dissipation of 1-nW order at 10 GHz. Logic and analog circuits using the device have been fabricated and tested. The device's margin may be reduced by a number of problems due to fabrication and design variations such as imbalance of Josephson-junction critical currents, flux loss in transformer self-inductances, and transformer coupling variations. The authors review these problems and describe three auxiliary circuits-booster, puller, and regulator-for alleviating them. A booster reduces the effect of critical current variations and doubles the output. A puller increases the activation current, thus allowing smaller clock signals. A regulator ensures full activation of the QFP over a wide range of activation levels. With these currents, the device has a much improved margin against variations originating from within itself.>

IEEE Transactions on Electron Devices•Jan 1, 1992•1 citation

Operation of a 1-bit quantum flux parametron shift register (latch) by 4-phase 36-GHz clock

M. Hosoya, W. Hioe, Kazumasa Takagi +1 more

The Quantum Flux Parametron (QFP) is a SFQ-type logic device which uses a single flux quantum (SFQ) to represent 1-bit of information. QFP circuits use a multi-phase external ac power which also acts as the clock for synchronization, hence QFP circuits are highly pipelined. The clock frequency must be increased to improve the throughputs of the circuits, so the control of a high frequency clock is a key technology for the QFP. This paper describes a clock distribution technique which utilizes the characteristics of a standing wave. Using this technique, the operation of a 1-bit QFP shift register by a 4-phase clock up to 36 GHz is shown. In the 4-phase clock operation of QFPs, the input is given in phase 1, the QFP switches in phase 2, the output is held during phase 3, and the QFP resets in phase 4. Therefore, the 4-phase 36-GHz operation means that each QFP switches or resets in less than 7 ps.>

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Quantum Flux Parametron

The Quantum Flux Parametron (QFP) is a new cryogenic switching device based on the parametron principle and Josephson technology. Due to the magnetic flux quantization in superconducting devices, the switching mechanism of the QFP is quite different from that of semiconductors. This presentation describes the device characteristics. QFPs have been fabricated using the Nb/Pb-alloy Josephson junction process, and their basic operation is evaluated. Over 20dB current gain is attained. One-half frequency-divider operation up to 1.8GHz has been successfully observed.

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JOSEPHSON SUPERCOMPUTER DESIGN USING QUANTUM FLUX PARAMETRON

Eiichi Goto, K. F. Loe

The Quantum Flux Parametron (QFP) is a Josephson Junction device using the polarity of a quantum magnetic flux to represent a binary information. A quantum unit of magnetic flux in a QFP can be controlled to realize majority logic operation, consequently AND and OR logics can be realized. Together with negation, which can be realized by a flux-inverting transformer, various computing logic devices can be constructed. In addition, the QFP is also a latching device so that a flux can be confined in the device to realize memory function. Due to the homogenous nature of memory and logic circuits as well as the flux nature of the signal which can be transmitted inductively, an entirely new Josephson supercomputer with memory and CPU pipelining arranged in a 3D setting was conceived. The computer with 40 processors is expected to run at a maximum speed of 20 GFLOPS of scalar processing.

International Journal of High Speed Computing•Jun 1, 1991•0 citations

Quantum flux parametron

Y. Harada, Eiichi Goto Eiichi Goto, N. Miyamoto

The Quantum Flux Parametron (QFP) is a new cryogenic switching device based on the parametron principle and Josephson technology. Due to the magnetic flux quantization in superconducting devices, the switching mechanism of the QFP is quite different from that of semiconductors. This presentation describes the device characteristics. QFPs have been fabricated using the Nb/Pb-alloy Josephson junction process, and their basic operation is evaluated. Over 20dB current gain is attained. One-half frequency-divider operation up to 1.8GHz has been successfully observed.

Technical digest - International Electron Devices Meeting/Technical digest•Jan 1, 1987•10 citations
A quantum flux parametron (QFP), a single quantum flux superconductive device that has a potential of up to 100-GHz switching with nW-order power dissipation, is considered. The potential of the QFP and key technologies when QFPs are applied to a Josephson supercomputer are described. Switching speed, stability, and power dissipation of a QFP are discussed. QFP gates, circuits, and systems are next described. Then, ultra-fast clock distribution using a standing wave is explained. High-speed operation at more than 10 GHz and 10/sup 14/ error-free operations per QFP have been demonstrated. Finally described is a high-density packaging scheme by three-dimensional integration, which is very important for ultra-high speed circuits because the propagation delay becomes dominant in such circuits.>
This book concerns a Josephson device for supercomputers which has extremely low heat dissipation (about 106 times less than semiconductor devices and 103 times less than voltage-based Josephson devices). In the previous book on Quantum Flux Parametrons (QFPs), DC Flux Parametron, the basic device operation are described. This book deals in much greater depth on the problems which are faced by the QFP. The device characteristics are worked out in detail showing clearly the analysis methods used. A new logic gate using the QFP is described with respect to its basic scheme, operation, and ways for forming logic circuits. The problems faced by the basic QFP are much reduced in the new logic gate. As the QFP operates near the Heisenberg and Boltzmann limits for computing devices, we also show the relationship between speed and stability. The book contains the latest analytical results on QFPs.The material presented in the book can be understood with very little mathematical training or knowledge about superconducting physics. It is also self-contained and does not require reading of other material. Most of the device characteristics can be reproduced from the equations given using simple programs. A circuit simulator is not needed except for high speeds when transient behavior becomes important.
The quantum-flux parametron (QFP) is a single-flux quantum Josephson device with a high gain of over 20 dB and a low power dissipation of 1-nW order at 10 GHz. Logic and analog circuits using the device have been fabricated and tested. The device's margin may be reduced by a number of problems due to fabrication and design variations such as imbalance of Josephson-junction critical currents, flux loss in transformer self-inductances, and transformer coupling variations. The authors review these problems and describe three auxiliary circuits-booster, puller, and regulator-for alleviating them. A booster reduces the effect of critical current variations and doubles the output. A puller increases the activation current, thus allowing smaller clock signals. A regulator ensures full activation of the QFP over a wide range of activation levels. With these currents, the device has a much improved margin against variations originating from within itself.>
The Quantum Flux Parametron (QFP) is a SFQ-type logic device which uses a single flux quantum (SFQ) to represent 1-bit of information. QFP circuits use a multi-phase external ac power which also acts as the clock for synchronization, hence QFP circuits are highly pipelined. The clock frequency must be increased to improve the throughputs of the circuits, so the control of a high frequency clock is a key technology for the QFP. This paper describes a clock distribution technique which utilizes the characteristics of a standing wave. Using this technique, the operation of a 1-bit QFP shift register by a 4-phase clock up to 36 GHz is shown. In the 4-phase clock operation of QFPs, the input is given in phase 1, the QFP switches in phase 2, the output is held during phase 3, and the QFP resets in phase 4. Therefore, the 4-phase 36-GHz operation means that each QFP switches or resets in less than 7 ps.>
The Quantum Flux Parametron (QFP) is a new cryogenic switching device based on the parametron principle and Josephson technology. Due to the magnetic flux quantization in superconducting devices, the switching mechanism of the QFP is quite different from that of semiconductors. This presentation describes the device characteristics. QFPs have been fabricated using the Nb/Pb-alloy Josephson junction process, and their basic operation is evaluated. Over 20dB current gain is attained. One-half frequency-divider operation up to 1.8GHz has been successfully observed.
The Quantum Flux Parametron (QFP) is a Josephson Junction device using the polarity of a quantum magnetic flux to represent a binary information. A quantum unit of magnetic flux in a QFP can be controlled to realize majority logic operation, consequently AND and OR logics can be realized. Together with negation, which can be realized by a flux-inverting transformer, various computing logic devices can be constructed. In addition, the QFP is also a latching device so that a flux can be confined in the device to realize memory function. Due to the homogenous nature of memory and logic circuits as well as the flux nature of the signal which can be transmitted inductively, an entirely new Josephson supercomputer with memory and CPU pipelining arranged in a 3D setting was conceived. The computer with 40 processors is expected to run at a maximum speed of 20 GFLOPS of scalar processing.
The Quantum Flux Parametron (QFP) is a new cryogenic switching device based on the parametron principle and Josephson technology. Due to the magnetic flux quantization in superconducting devices, the switching mechanism of the QFP is quite different from that of semiconductors. This presentation describes the device characteristics. QFPs have been fabricated using the Nb/Pb-alloy Josephson junction process, and their basic operation is evaluated. Over 20dB current gain is attained. One-half frequency-divider operation up to 1.8GHz has been successfully observed.