Implementation of Interface Circuit for Digital SQUID with Sub-Flux Quantum Feedback Resolution. (July 2020)

• Record Type: Journal Article
• Authors: Matsunawa, Ryo; Itagaki, Kohki; Oshima, Itta; Hasegawa, Yuichi; Naruse, Masato; Taino, Tohru; Myoren, Hiroaki
• Is Part Of: Journal of physics. Volume 1590(2020)
• Publication Date: 2020-07
• Subjects: Physics -- Congresses; 530.5
• DOI: 10.1088/1742-6596/1590/1/012039
• Languages: English
• ISSNs: 1742-6588

Abstract

Abstract: Digital SQUIDs with single flux quantum (SFQ) feedback have attracted much attention because of the feasibility of realizing a wide dynamic range and high slew rate for digital magnetometers. To achieve a higher resolution, we studied a digital SQUID with sub-flux quantum feedback. We studied implementation methods for an interface circuit by considering the circuit size, power consumption and signal processing to achieve high-resolution and highspeed operation of the digital SQUID magnetometer. Assuming the decimation filter and the up/down counter implemented on a FPGA board, a 1-bit to 16-bit deserializer with an output frequency of 500 MHz could be used for the interface circuit. The circuit scale was 1940 µ m × 1720 µ m, and the bias current was 302 mA. From the simulation results, a sufficient wide bias margin could be obtained up to 30 GHz.