3D Hall probe integrated in 0.35 μm CMOS technology for magnetic field pulses measurements

This paper presents a 3 dimensional magnetometer based on Hall effect sensors integrated without any post processing in a standard low cost 0.35 mum CMOS technology. The system is dedicated to magnetic pulses measurements under a strong static field. Two vertical Hall devices (VHD) are sensitive to the components of the magnetic field oriented in the plane of the chip, while a horizontal Hall device (HHD) is sensitive to the component of the magnetic field orthogonally oriented to the plane of the chip. 3 identical instrumental chains are integrated to perform amplification of the 3 Hall voltages. The system implements a compensation of the static magnetic field and allows to measure magnetic fields pulses with a resolution of 79 muT over a [5 Hz - 1.6 kHz] bandwidth. Pulses are in the range from hundreds of muT to tens of mT in the frequency range from 1 Hz to 10 kHz. The static field is compensated up to 1.5 T. The spatial resolution is 44 mum. The system power consumption has been optimized to 15 mW.