An Integrated Microsystem for 3D Magnetic Field Measurements

Abstract—In this paper, we present a portable, battery-op-erated, three-dimensional magnetic microsystem (magneto-dosimeter), intended for monitoring the workers ’ exposure to magnetic fields in particular working environments, such as hospitals or physics laboratories. The proposed microsystem is based on a multichip module containing three equal channels for the three components of the magnetic field measurement, a microprocessor, and a memory. Each single-chip channel detects the magnetic field, converts it into the digital domain, and delivers the result to the microprocessor by means of an on-chip serial interface. The single-chip channel, fabricated in a 0.8-m CMOS technology, is sensitive to magnetic fields ranging from 200 to +200 mT, achieving 12 bits of resolution, 11 bits of linearity, and an overall accuracy better than 1 % in the temperature range from 20 to +80 C. Index Terms—Analog–digital conversion, CMOS integrated circuits, magnetic field measurement, magnetic transducers, microsensors, sigma–delta modulation. I