An Intrinsically Temperature-Drift Suppression Phase-Locked Loop With MEMS Voltage Controlled Oscillator for Micromechanical Resonant Accelerometer

MEMS resonant accelerometers are robust to electromagnetic interference and have higher sensitivity and resolution. However, they are susceptible to temperature variation, which may limit this type of sensor used in high-end applications. This paper proposes a TDS-PLL with MEMS VCO for MEMS resonant accelerometers to be immune to temperature drift. The theoretical analysis of TDS-PLL MRA demonstrates it can suppress the temperature drift, which is verified by simulation and measurement results. Measurement results of the TDS-PLL MRA show that the bias instability is <inline-formula> <tex-math notation="LaTeX">$13.15~\mu \text{g}$ </tex-math></inline-formula> and the noise level is <inline-formula> <tex-math notation="LaTeX">$7.04~\mu \text{g}/\surd $ </tex-math></inline-formula> Hz with 0.32g full scale at room temperature. The temperature coefficient of bias stability in TDS-PLL MRA achieves 2.21 mg/°C in a temperature range of 300K to 360K, which is lower 5.5 times than that of the traditional PLL MRA with frequency shift. [2022-0098]