Compact Mems Temperature Sensor Exploiting A Dual-Mode Polysilicon Resonator And Phase-Locked-Loop Multiplication

The paper reports a (200 x 50) μm
²
temperature sensor exploiting two simultaneously vibrating modes of a polysilicon microelectromechanical system (MEMS) resonator, with slightly different temperature coefficients. Their frequency is processed by phase-locked-loops (PLL), with different division factors, enabling a larger separation of output frequencies, thus reducing quantization errors. Results show a ±0.05 °C
rms
resolution at 4-Hz output-data-rate (ODR). Such a resonator can be used in the same die of another sensor, for its accurate temperature calibration.