As the automotive industry continues to add sophisticated electronic systems, the need for reliable and robust automotive-grade timing solutions increases. Soon cars will need upwards of 70 timing devices. For several decades, timing components were based on quartz crystal technology—previously the only viable option that offered high stability and performance. However, precision MEMS (micro-electro-mechanical systems) timing solutions are rapidly becoming the technology of choice because they offer the highest performance and reliability. Additionally, these MEMS timing solutions have unique features that solve longstanding timing problems-features that are required for emerging automotive applications as the industry moves toward autonomous driving with complete connectivity and safety.

MEMS timing solutions are completely fabricated in silicon, using standard semiconductor manufacturing practices. SiTime resonators are produced using the patented MEMS First® and EpiSeal® manufacturing processes that anneal the resonator at 1100°C. This high-temperature process produces a high-quality resonator that is hermetically sealed without contaminants that could lead to mass-loading of the resonator and cause frequency drift. The resonator is fully encapsulated within a silicon die, making it extremely resistant to damage from external sources. 

MEMS oscillators are assembled using a stacked die configuration. Compared to quartz packages, MEMS packages have a lower profile, yet they fit common quartz oscillator PCB pad layout and are pin compatible to quartz devices for easy drop-in replacement. 

Vehicles are subject to harsh environments such as high levels of mechanical shock and vibration forces that can degrade quartz oscillator performance and cause them to fail. While operating in these conditions, an oscillator must conform to its specifications. If the oscillator is not reliable, it has the potential to cause catastrophic failure. MEMS resonators are less susceptible to vibration because they have the lighter mass than quartz resonators. This reduces the force applied to the resonator from vibration induced acceleration. 

MEMS oscillators are also resilient against power supply noise which is amplified when the power supply and other devices on the board turn on and off. This can increase the jitter on the output clock and negatively impact system timing margins. For example, in ADAS systems, when jitter worsens, it can affect how quickly data is sent from sensors to the decision engine. On the road where vehicle surroundings are constantly changing, a lag in data transmission can be devastating.

SiTime automotive timing products have a programmable architecture that enables short lead times and allows designers to select from a range of specifications including any frequency within the operating range, with up to six decimal places of accuracy.