A miniaturized magnetic field sensor system consisting of a planar fluxgate sensor and a CMOS readout circuitry

We report on a miniaturized magnetic field sensor system consisting of a fluxgate sensor fabricated in CMOS-compatible planar technology and a CMOS-ASIC for sensor supply, readout and signal processing using second harmonic principle with a feedback loop for zero field operation. The system exhibits a sensitivity of (9.2ñ0.1) mV/µT for a magnetic field range of ñ90µT and a temperature range of 0øC to 70øC. The 3 dB bandwith is 300 Hz and a noise value of 30 nT/(Hz)1/2 was estimated. Using 5V supply voltage a power consumption of 160mW for the system was measured.