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This paper presents a new design and a complete characterization of amplitude-modulation gyroscopes based on piezoresistive nanogauges. The working principle and optimization criteria of in-plane and out-of-plane devices relying on double frame decoupling and levered sense mode are discussed in light of sensitivity and resolution theoretical predictions. The architecture of driving and sensing electronics is also presented. The reduced thermo-mechanical damping with respect to capacitive configurations, and the inherently high output signal leads to white noise performance in the mdps/ √ Hz range within an area smaller than 0.35 mm 2 , at pressures in the millibar range. Sub-5-ppm linearity errors within 1000 dps are also demonstrated.[2015-0064]

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This paper reports the developments towards an integrated, triaxial, frequency-modulated, consumergrade, MEMS gyroscope. A custom low-power (160 µA), low-phase-noise integrated circuit is designed specifically for frequency-modulated operation. Both yaw-and pitchrate sensing systems are demonstrated, by coupling the circuit with two novel micromachined structures fabricated with a 24-µm-thick industrial process. In operation, both gyroscopes show a repeatable and stable scale factor, with less than 0.55% of part-to-part variability, obtained without any calibration, and 35 ppm/ • C of variability over a 25 • to 70 • C temperature range.

The work presents a microelectromechanical system (MEMS) based magnetometer, targeting compass applications performance, which measures magnetic fields along an in-plane direction. The magnetometer is fabricated with the surface micromachining process used for consumer gyroscopes, accelerometers, and recently proposed out-of-plane magnetometers. The magnetometer is based on the Lorentz force principle, so to avoid the need for magnetic materials integration. It features an area of 282 x 1095 µm 2 , and it is wafer-wafer packaged at a nominal pressure (0.35 mbar) similar to the one used for gyroscopes. In agreement with theoretical predictions, operation is demonstrated both at-resonance and off-resonance: in both situations the measured resolution, normalized to unit bandwidth and applied Lorentz current, is about 120 nT·mA/ √ Hz, but the maximum sensing bandwidth is extended from 4 Hz (at resonance) to 42Hz in off-resonance mode, which copes with consumer specifications. Within magnetic fields of ±5 mT, the device shows measured linearity errors <0.5% of the full-scale-range (demonstrating a large linearity) and a cross-axis rejection of ∼50 dB. The bias stability in off-resonance operation mode (80 nT·mA at 100 s) improves by a factor 100 with respect to resonance operation.