ASIC Current-Reuse Amplifier With MEMS Delta-E Magnetic Field Sensors
An application specific integrated circuit (ASIC) and a custom-made microelectromechanical system (MEMS) sensor are presented, designed to function together as a sensor system for measuring low amplitude low frequency magnetic fields. The MEMS system comprises several free-standing double-wing magne...
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| Main Authors: | , , , , , |
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| Format: | Article |
| Language: | English |
| Published: |
IEEE
2024-01-01
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| Series: | IEEE Open Journal of Circuits and Systems |
| Subjects: | |
| Online Access: | https://ieeexplore.ieee.org/document/10801234/ |
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| Summary: | An application specific integrated circuit (ASIC) and a custom-made microelectromechanical system (MEMS) sensor are presented, designed to function together as a sensor system for measuring low amplitude low frequency magnetic fields. The MEMS system comprises several free-standing double-wing magnetoelectric resonators with a size of <inline-formula> <tex-math notation="LaTeX">$900~\mu $ </tex-math></inline-formula>m x <inline-formula> <tex-math notation="LaTeX">$150~\mu $ </tex-math></inline-formula>m to measure alternating magnetic fields in the sub-kilohertz regime. It utilizes piezolelectric (AlN) and magnetostrictive (FeCoSiB) layers to exploit the delta-E effect for magnetic field sensing. On the ASIC a three-channel current-reuse amplifier with lateral bipolar transistors in the input stage is implemented occupying a chip area of 0.0864 mm2. Measurements demonstrate a voltage gain of 40 dB with a 3-dB bandwidth of 75 kHz and an input referred noise floor of 8 nV/<inline-formula> <tex-math notation="LaTeX">$\surd $ </tex-math></inline-formula>Hz while consuming <inline-formula> <tex-math notation="LaTeX">$199~\mu $ </tex-math></inline-formula>W per channel. The sensor system is capable of detecting magnetic fields with a limit of detection (LOD) of 16 nT/<inline-formula> <tex-math notation="LaTeX">$\surd $ </tex-math></inline-formula>Hz for single sensor elements. By operating three sensor elements in parallel, one on each amplifier channel, the LOD is further reduced to 10 nT/<inline-formula> <tex-math notation="LaTeX">$\surd $ </tex-math></inline-formula>Hz. Owing to the high reproducibility of the sensor elements, this improvement in the LOD is close to the ideal value of <inline-formula> <tex-math notation="LaTeX">$\surd 3$ </tex-math></inline-formula>. The results imply that the system can be scaled to large numbers of sensor elements without principle obstacles. |
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| ISSN: | 2644-1225 |