Markus Lutz is CTO and Founder of SiTime Corporation. He is a MEMS expert, a prolific entrepreneur and inventor who holds over 100 patents.
America’s love affair with the automobile is boundless. Our cars provide all the comforts, conveniences and infotainment we desire, as well as the safety and autonomous features of advanced driver assistance systems (ADAS). Today’s vehicles are not just “cars”—they’re highly computerized, intelligent, automated, connected and sensor-laden mobile systems built on a rolling chassis.
Much of this functionality depends on the electronic content in cars. Automotive is one of the fastest-growing markets in the semiconductor sector, and electronic components for electric vehicles and ADAS are key drivers of this growth. According to the U.S. International Trade Commission (USITC), conventional internal combustion engine (ICE) vehicles contain a typical semiconductor value of $330, while hybrid electric vehicles contain from $1,000 to $3,500 worth of semiconductors. The average car is packed with 1,400 semiconductors, controlling everything from safety systems to the drivetrain.
Trends Fueling The Upsurge Of Semiconductor Content In Automotive
With the rise of vehicle electrification, electric powertrains for battery electric and hybrid electric vehicles (BEVs/HEVs) require numerous specialized chips for power and battery management systems. The BEV/HEV market will continue to grow steadily this decade as automakers phase out internal combustion engine models. Lower battery costs, longer battery life, improved charging capabilities and extended EV driving range will further speed automotive electrification.
Increasingly autonomous vehicles equipped with ADAS require fast, reliable communications within the car and over wireless networks. Numerous sensors (vision, proximity, temperature, pressure, etc.) generate enormous amounts of real-time data to be processed by networked in-vehicle computing systems and communicated externally through mobile networks. A tech-laden car can generate two terabytes of data per hour, which is expected to increase to 20 TB per hour by 2025.
Precise, Reliable Timing Technology Keeps Automotive Systems In Sync
To keep complex automotive systems operating in harmony, today’s cars use up to 70 timing devices, and that number is growing with the adoption of smarter technology with each new automotive generation. Timing technology is the heartbeat of everything with an electronic pulse, from consumer electronics and IoT devices to networking and wireless infrastructure to industrial and automotive. In automotive systems, timing components synchronize critical clocking functions within electronic control units for ADAS, vehicle networking, infotainment and other subsystems.
While the pace of automotive innovation continues to accelerate, one critical type of timing component remains stuck in the slow lane: timing devices based on quartz crystals. As the complexity of automotive systems increases, the use of quartz devices is becoming a bottleneck for reliability and safety due to drawbacks and limitations, which drive up cost and limit system reliability.
Automotive electronics operate in unforgiving environments subject to vibration, shock and electromagnetic interference. Constant vibration from rough roads, speed bumps and moving parts, as well as constant electromagnetic interference (EMI) generated by tightly integrated electronic components, can take a toll on sensitive electronics such as quartz timing devices. EMI, for example, can damage electronic components, causing them to malfunction or fail, and can also impact a device’s ability to send or receive signals.
Automotive applications also require extended temperature operation, typically in the −40 °C to +125 °C range. Additionally, the industry is seeing demand for temperature operation as high as +150 °C for demanding automotive designs. Changing weather conditions as well as heat generated by the engine or battery packs can drive extreme temperature fluctuations, which can significantly degrade the accuracy of quartz-based components. The susceptibility of quartz timing references to environmental stressors can negatively impact the performance and long-term reliability of automotive systems.
Automotive Clocking Technology Options And Considerations
Automakers design cars to work reliably for many years while operating in harsh conditions, but if a component or system malfunctions, we still expect our cars to operate safely at all times. Timing chips must never be a weak link. Timing technology provides a mission-critical function in automotive, placing extreme demands on clock sources. Even if an automotive component or system goes awry, clock signals must continue operating without fail.
As an alternative to quartz components, microelectromechanical system (MEMS) technology has emerged as a primary timing source for automotive applications, such as ADAS and EV power and battery management systems, which require exceptional reliability while handling environmental stressors. Like their quartz counterparts for automotive, MEMS timing components are designed to meet rigorous AEC-Q100 automotive qualification requirements. This industry qualification assures automakers that their timing components, whether quartz or MEMS-based, provide the robustness, reliability and performance demanded by automotive electronic systems.
While quartz-based timing components intended for automotive systems are designed and tested for high reliability, MEMS timing devices are more robust and reliable, delivering more than a billion hours of mean time between failures (MTBF) compared to quartz, with as little as 50 million hours MTBF.
When developers evaluate MEMS- and quartz-based timing components for their automotive system designs, they assess a range of variables, including package size, input voltage and power, jitter performance, output frequency, output waveform, frequency stability and temperature range. Depending on the MEMS timing device provider they choose, automakers and Tier 1 suppliers wanting to get started with MEMS technology can source MEMS-based oscillators and clocks that are “plug and play” equivalents of quartz-based products.
A barrier to broader acceptance of MEMS timing in automotive involves a market perception of relatively new technology like MEMS timing versus the status quo. Since many developers have used quartz products for years, it’s often a matter of comfort level and familiarity in making the switch to MEMS. There also can be concerns around dual sourcing, which is the industry practice of ensuring at least two suppliers for a given component. However, because there are multiple MEMS timing device manufacturers, dual sourcing is not an issue.
The upside of using quartz-based timing supplies is that it’s a familiar, market-proven technology that has been used in automotive designs for decodes. While MEMS-based components are a more recent advancement, they provide a reliable, robust timing solution with a resilient supply chain to help keep automotive innovation rolling forward.