A frontend for magnetoresistive sensors with a 2.2 pA/√Hz low-noise current source

Mohamed, A., Wagner, M., Heidari, H. and Anders, J. (2022) A frontend for magnetoresistive sensors with a 2.2 pA/√Hz low-noise current source. IEEE Solid-State Circuits Letters, 5, pp. 17-20. (doi: 10.1109/LSSC.2022.3148362)

Abstract

In this letter, we present an integrated readout chip for magnetoresistive (MR) sensors consisting of a readout chain that comprises a DC-coupled fully differential difference amplifier (FDDA) followed by a programmable gain amplifier (PGA), as well as a low-noise current biasing scheme for the MR sensor. The current bias scheme features a 10-bit digital-toanalog converter (DAC) to compensate for process variations of the MR sensing element as well as to calibrate for variations in the DC bias field of the sensor. The bias current source achieves a very low current noise floor of 2.2pA/√Hz for bias currents up to 1mA. The readout chip is manufactured in 180nm SOI CMOS and consumes a total power of 38mW. The paper is an extended version of 1, incorporating additional modeling details and measurement results.

• Item Type: Articles
• Additional Information: This work is supported by the Carl Zeiss Foundation and the German Research Foundation (DFG) under contract no. AN 984/12-1.
• Status: Published
• Refereed: Yes
• Glasgow Author(s) Enlighten ID: Heidari, Professor Hadi
• Authors: Mohamed, A., Wagner, M., Heidari, H., and Anders, J.
• College/School: College of Science and Engineering > School of Engineering > Electronics and Nanoscale Engineering
• Journal Name: IEEE Solid-State Circuits Letters
• Publisher: IEEE
• ISSN: 2573-9603
• ISSN (Online): 2573-9603
• Published Online: 02 February 2022
• Copyright Holders: Copyright © 2021 IEEE
• First Published: First published in IEEE Solid-State Circuits Letters 5: 17-20
• Publisher Policy: Reproduced in accordance with the publisher copyright policy