Multilayer HTS SFQ analog-to-digital converters

Author

McCambridge, J.D. ; Forrester, M.G. ; Miller, D.L. ; Hunt, B.D. ; Pryzbysz, J.X. ; Talvacchio, J. ; Young, R.M.

Author_Institution

Northrop Grumman Sci. & Technol. Center, Pittsburgh, PA, USA

Volume

7

Issue

2

fYear

1997

fDate

6/1/1997 12:00:00 AM

Firstpage

3622

Lastpage

3625

Abstract

We have fabricated and measured high T/sub c/ superconductor single flux quantum 1-bit flux-counting analog-to-digital converters (ADCs). The ADCs were made with a multilayer all-epitaxial process which incorporates 10 edge SNS (superconductor-normal-superconductor) or step-edge grain boundary (SEGB) Josephson junctions with a YBa/sub 2/Cu/sub 3/O/sub 7-/spl delta// groundplane. The ADC consists of a quantizer connected to a Toggle flip-flop through a buffer-like stage. Direct readout of the flux state of the T flip-flop was made with a Read SQUID inductively coupled through a hole in the groundplane. The circuits were operated at 65 K and low speeds. The SNS circuits outperformed the SEGB circuits because of their higher readout voltages and tighter critical current spreads.

Keywords

analogue-digital conversion; barium compounds; grain boundaries; high-temperature superconductors; superconducting epitaxial layers; superconducting junction devices; yttrium compounds; 1 bit; 65 K; YBa/sub 2/Cu/sub 3/O/sub 7-/spl delta// groundplane; YBa/sub 2/Cu/sub 3/O/sub 7/; all-epitaxial process; buffer stage; critical current; direct readout voltage; edge SNS Josephson junction; high T/sub c/ superconductor; multilayer HTS SFQ ADC circuit; quantizer; read SQUID; single flux quantum flux-counting analog-to-digital converter; step-edge grain boundary Josephson junction; toggle flip-flop; Analog-digital conversion; Coupling circuits; Flip-flops; Grain boundaries; High temperature superconductors; Josephson junctions; Nonhomogeneous media; SQUIDs; Superconducting devices; Voltage;

fLanguage

English

Journal_Title

Applied Superconductivity, IEEE Transactions on

Publisher

ieee

ISSN

1051-8223

Type

jour

DOI

10.1109/77.622201

Filename

622201