Editor’s note: We welcome a new guest blogger this week: Alan K. Mond, EVP Sales and Marketing, Sand 9 Inc.
Click on any tech article today and chances are the subject matter will be about the huge growth in IoT (Internet of Things). From smartphones to wearables, from smart thermostats to smart lighting, and from smart cars to smart industry, everybody is looking to capture a share of what is expected to be the largest growth market in the next three to five years, and MEMS is playing a key role in enabling differentiation across the value chain.
Fundamentally, IoT is an ecosystem where devices that either contain or have access to sensors are connected to the Internet via a broadband connection, either wired or wireless. Industry reports on market size vary. Last year Gartner published its forecast, “The Internet of Things, Worldwide 2013,” and suggests that the total number of connected devices will grow to 26 billion by 2020, which will provide $1.9 trillion in economic value-add, whereas Cisco Systems puts that number at 50 billion devices and the “value at stake” at $14.4 trillion. Regardless of the final market size, it is clear that the growth in IoT will be unprecedented with respect to anything seen since the industrial revolution.
One major area that has helped enable the growth in IoT has been the availability of components and semiconductors that support these new smart devices. These items include sensors, controllers, and most importantly communications chips that support not only broadband cellular transmissions (3G and LTE), but also GNSS/GPS and other short-range wireless connectivity chips (WiFi, Bluetooth, ZigBee, etc.). A summary table of protocols and applications is listed below.
As the number of ICs supporting the above protocols has increased, the number of semiconductor companies offering connectivity integrated circuits (ICs) to IoT OEMs has also grown. Heightened competition in a standards-dominated market is driving semiconductor companies to seek out opportunities to differentiate by offering lower cost and smaller size, while enabling new features. The drive to differentiate is creating new opportunities for MEMS.
One important trait all the ICs share is the need to be clocked by a reliable reference source. Today, quartz devices are ubiquitous components in all wireless communication devices. Despite their dominance, they are now under significant threat from silicon-based MEMS timing devices, which today offer a real alternative to quartz, with many advantages that are integral for success in IoT applications, for example:
Size/power. Quartz crystals are limited in size, due to the physics required to maintain a size-to-thickness ratio. This poses a significant dilemma for the semiconductor designer. Ideally, semiconductor designers like to use low-frequency clock references in the range of 12-26 MHz. The use of lower frequencies reduces power consumed within the clocking system, which improves battery life. Unfortunately, at low frequencies the physics of quartz means that it is typically housed in a large, 3.2×2.5 mm ceramic package, external to the IC in question.
Designers can opt to move to higher frequencies, resulting in smaller package sizes, but this ultimately leads to higher power consumption. MEMS resonators, in contrast, do not suffer from the same physical constraints as quartz. In fact, in the case of piezoelectric MEMS resonators, frequencies from 12 MHz to 150 MHz can be obtained without trading off size. Today, piezoelectric MEMS resonators are available in an ultra-small 0.72×0.80 mm CSP, a reduction of over 14X when compared to traditional quartz. This size advantage also allows semiconductor designers (for the first time) to integrate timing with their ICs to offer a true system-on-chip (SoC) or system-in-package (SiP) solution to their customers.
Resistance to shock and vibration. Quartz crystals are extremely fragile, and susceptible to failure when subjected to repeated shock and/or vibration. MEMS, on the other hand, because of its low resonator mass and monolithic structure, can withstand an order of magnitude greater level of both shock and vibration. This opens up new markets in industrial IoT applications where vibration can be a major cause of failure (e.g., wind turbines and engine management) as well as in consumer IoT applications that are subject to shock (Nike+ shoes, for example).
Cost. Unlike quartz crystals that are assembled individually, piezoelectric MEMS manufacturing is based on leveraging semiconductor manufacturing processes and wafer bonding techniques. Devices are built on 8-inch wafers at a density that allows for manufacturing costs lower than those of traditional quartz, enabling OEMs to reduce their overall BOM costs.
Today, the availability of piezoelectric MEMS timing devices provides a paradigm shift in the way the semiconductor industry considers timing for IoT applications. By integrating MEMS resonators, semiconductor companies can provide a differentiated SoC solution that offers new features, performance, and cost advantages to the evolving IoT market.