100 µA, 320 nT/vHz, 3-AXIS Lorentz force MEMS magnetometer

The work presents a module for earth magnetic field measurements based on four microelectromechanical devices: one out-of-plane and two in-plane differential Lorentz-force magnetometers, and a Tang resonator. The latter is used to provide the reference frequency in off-resonance operation, a way that enables the magnetometers to share the same Lorentz current, giving an intrinsic 3-fold consumption decrease. At the same time, using multiple-loop design, a 5-fold larger sensitivity and a 4-fold better resolution are obtained with respect to previous implementations that used the same process. The system operating bandwidth is electronically selectable up to 50 Hz.