Signal resolution of RSFQ comparators

Author

Filippov, T.V. ; Polyakov, Y.A. ; Semenov, V.K. ; Likharev, K.K.

Author_Institution

State Univ. of New York, Stony Brook, NY, USA

Volume

5

Issue

2

fYear

1995

fDate

6/1/1995 12:00:00 AM

Firstpage

2240

Lastpage

2243

Abstract

We have designed and tested a Rapid Single-Flux-Quantum (RSFQ) circuit for experimental measurement of the fluctuation-induced threshold uncertainty of switching of SFQ comparators, which are essential components of RSFQ logic devices, analog-to-digital converters, and digital SQUIDs. Statistical density of the switching events in comparators using externally-overdamped Nb-trilayer Josephson junctions has been found to be in agreement with the distribution which follows from a simple theory based on a time-dependent harmonic-oscillator model of the device. Width of the distribution (i.e, the single-shot current resolution of the comparator) measured as a function of temperature in the range 1.7-4.2 K corresponds to fundamental (thermal/quantum) fluctuations, with no evidence of excess noise sources.<>

Keywords

Josephson effect; analogue-digital conversion; current comparators; signal resolution; superconducting device noise; superconducting logic circuits; superconducting switches; 1.7 to 4.2 K; Josephson junction switching dynamics; Nb; RSFQ comparators; RSFQ logic devices; analog-to-digital converters; digital SQUIDs; externally-overdamped Nb-trilayer Josephson junctions; fluctuation-induced threshold uncertainty; quantum fluctuations; rapid single-flux-quantum circuit; signal resolution; single-shot current resolution; switching event statistical density; thermal fluctuations; time-dependent harmonic-oscillator model; Analog-digital conversion; Circuit testing; Current measurement; Josephson junctions; Logic devices; Logic testing; Noise measurement; SQUIDs; Signal resolution; Switching circuits;

fLanguage

English

Journal_Title

Applied Superconductivity, IEEE Transactions on

Publisher

ieee

ISSN

1051-8223

Type

jour

DOI

10.1109/77.403031

Filename

403031