학술논문

A semi-custom design methodology and environment for implementing superconductor adiabatic quantum-flux-parametron microprocessors.
Document Type
Article
Source
Superconductor Science & Technology. May2020, Vol. 33 Issue 5, p1-16. 16p.
Subject
*MICROPROCESSORS
*SUPERCONDUCTORS
*LINE drivers (Integrated circuits)
*LOGIC circuits
*JOSEPHSON junctions
Language
ISSN
0953-2048
Abstract
We present a comprehensive overview of a design methodology and environment that we developed to enable the implementation of microprocessors and other complex logic circuits using the adiabatic quantum-flux-parametron (AQFP) superconductor logic family. The design environment is catered for both the AIST 10 kA cm−2 Nb high-speed standard process as well as the AIST 2.5 kA cm−2 Nb standard process (STP2). We detail each aspect of the design flow, highlighting improvements in cell design, and new developments in circuit retiming to reduce the number of synchronizing buffers in the circuit datapath. With retiming, we expect a 14–37% reduction in the overall Josephson junction (JJ) count for some benchmarks. Finally, we show the successful experimental demonstration of an arithmetic logic unit and data shifter for an AQFP microprocessor using the established methodology and environment. The demonstrated circuits show full functionality and wide excitation current margins of nearly ±30%, which corresponds well with simulation results. [ABSTRACT FROM AUTHOR]