A 737nA Always-On MEMS Gyroscope with 5.45ms Start-up Time Using Burst Mode PLL Technique

MEMS gyroscopes are widely used in mobile devices with optical image stabilization, augmented reality and indoor navigation. As one of the most power-hungry components, the MEMS gyroscopes are frequently powered down and started up to extend battery life. The conventional MEMS gyroscope suffers from long start-up time (>200ms) due to the high-Q sensing element [1]–[3]. The MEMS gyroscopes with always-on mode are reported to break this limitation and achieve a shortest start-up time of 30ms, but with significant always-on current consumption $(5\mu\mathrm{A})[4,5]$ . This paper presents an always-on MEMS gyroscope using the burst mode PLL technique. It achieves a start-up time of 5.45ms and an always-on current consumption of 737nA, which are 5.5x and 6.8x better than that of the state-of-the art, respectively.