SQUID operational amplifier

Author

Irwin, K.D. ; Huber, M.E.

Author_Institution

Nat. Inst. of Stand. & Technol., Boulder, CO, USA

Volume

11

Issue

1

fYear

2001

fDate

3/1/2001 12:00:00 AM

Firstpage

1265

Lastpage

1270

Abstract

The nonlinear response of Superconducting Quantum Interference Devices (SQUIDs) has limited their usefulness. We describe the SQUID Operational Amplifier, which consists of several stages of SQUIDs with high open-loop current gain. When connected in a negative-feedback configuration by passing some of the output current through a feedback coil connected to the first stage, the response is linearized. An analog of the semiconductor op-amp, the SQUID op-amp can be used in superconducting equivalents of op-amp circuits such as current amplifiers, current-to-voltage converters, and differentiators. We present experimental results with a ×10 current amplifier as well as a 750 Ω current-to-voltage amplifier which can couple directly to a room-temperature amplifier without a transformer or a feedback line

Keywords

DC amplifiers; SQUIDs; convertors; feedback amplifiers; operational amplifiers; superconducting integrated circuits; 750 ohm; SQUID operational amplifier; current amplifiers; current-to-voltage amplifier; current-to-voltage converters; differentiators; direct coupling; feedback coil; high open-loop current gain; linearized response; negative-feedback configuration; output current; room-temperature amplifier; Bandwidth; Circuits; Costs; Feedback; Inductance; Operational amplifiers; Resistors; SQUIDs; Superconducting coils; Voltage;

fLanguage

English

Journal_Title

Applied Superconductivity, IEEE Transactions on

Publisher

ieee

ISSN

1051-8223

Type

jour

DOI

10.1109/77.919580

Filename

919580