Title :
A new A/D converter with quantum flux parametron
Author :
Shimizu, Nobuhiro ; Harada, Yutaka ; Miyamoto, Nobuo ; Goto, Eiichi
Author_Institution :
Res. Dev. Corp. of Japan, Tokyo, Japan
fDate :
3/1/1989 12:00:00 AM
Abstract :
A flash-type superconducting A/D (analog/digital) converter is proposed. The basis low-frequency operation of this converter, which compromises a quantum flux parametron (QFP) and an RF SQUID (superconducting quantum interference device), has been observed. The RF SQUID consists of a Josephson junction and a load inductor which is part of the QFP. It converts an analog signal to period digital signals of one quantum flux (2.07×10-5 W-b) per cycle. The QFP works as both an amplifier and a comparator of the periodic digital signals, by adding an exciting signal. This A/D converter is expected to achieve high-speed operation of 20 GHz. Several 4-bit A/D converter circuits were fabricated, using the conventional Nb-Pb alloy process, with a junction size of 5 μm×5 μm and supercurrent density of 200 A/cm2. Basic operation at 100 KHz was confirmed experimentally
Keywords :
SQUIDs; analogue-digital conversion; superconducting junction devices; 100 kHz; 4 bit; A/D converter; Josephson junction; RF SQUID; amplifier; comparator; exciting signal; flash-type superconducting ADC; high-speed operation; load inductor; low-frequency operation; periodic digital signals; quantum flux parametron; supercurrent density; Analog-digital conversion; Circuits; Electronics packaging; Inductors; Josephson junctions; Radio frequency; Radiofrequency amplifiers; Radiofrequency interference; SQUIDs; Superconducting devices;
Journal_Title :
Magnetics, IEEE Transactions on
