A Low Phase Noise Piezoelectric MEMS Oscillator with Low Power Consumption

This work reports a complete demonstration of chip-level low phase noise and low power MEMS oscillator design in 17.55 MHz using a thin-film piezoelectric on silicon (TPoS) technology together with TSMC 0.18 μm CMOS technology node. In such an oscillator design, a four-resonator coupled array with equivalent motional resistance similar to quartz and a self-biased cross-coupled pair are implemented. As a result, a record-low phase noise of piezoelectric MEMS oscillator is measured with -136 dBc/Hz at 1 kHz offset under 154 μW DC power consumption in air while -137 dBc/Hz at 1 kHz offset under 148 μW in vacuum. As compared to the state-of-the-arts, the phase noise of the proposed oscillator in air is still at least 3 dB lower than that of other works operating in vacuum.