By Topic

Design of front-end circuit for Superconductive A/D converter and demonstration of operation up to 43 GHz

Sign In

Cookies must be enabled to login.After enabling cookies , please use refresh or reload or ctrl+f5 on the browser for the login options.

Formats Non-Member Member
$33 $13
Learn how you can qualify for the best price for this item!
Become an IEEE Member or Subscribe to
IEEE Xplore for exclusive pricing!
close button

puzzle piece

IEEE membership options for an individual and IEEE Xplore subscriptions for an organization offer the most affordable access to essential journal articles, conference papers, standards, eBooks, and eLearning courses.

Learn more about:

IEEE membership

IEEE Xplore subscriptions

3 Author(s)
F. Furuta ; Adv. Res. Lab., Hitachi Ltd., Tokyo, Japan ; K. Saitoh ; K. Takagi

We designed a front-end circuit for an analog-to-digital (A/D) converter based on single flux quantum circuitry and tested its functionality at a frequency of up to 43 GHz. The front-end circuit consisted of a pulse generator, a sigma-delta modulator, a 1-to-8 demultiplexer (DEMUX), and superconducting quantum interference device (SQUID) amplifiers. There were 2518 Josephson junctions in the front-end circuit. To operate the circuit at high speed, we designed robust timing against variations in circuit parameters. By using circuit simulations based on the Monte Carlo method, we estimated spread in time lag between clock and data pulses. From this estimate, the timing was optimized to operate the circuit at 40 GHz. The demonstration of the front-end circuit was carried out using the on-chip testing method. Output data were acquired from the modulator through DEMUX. We confirmed proper sigma-delta modulation by analyzing the dependence of the density "1" in the output data on input current level. The proper operation was confirmed in a range of 37-43 GHz. Furthermore, the amplification by the SQUID amplifier was also confirmed at low speed. These results indicate the complete operation of the front-end circuit for superconductive A/D converter.

Published in:

IEEE Transactions on Applied Superconductivity  (Volume:14 ,  Issue: 1 )