Ceramic-based electrical components for automotive applications have become exponentially more sophisticated while their size continues to decrease.

Madison Avenue’s slick car ads often highlight different driving conditions to showcase key selling points like safety and audio-visual equipment. What the ads neglect to illustrate, though, are the nuts and bolts behind these features. While everyone has watched commercials that focus on a powerful V-8 engine, no one has seen a television spot that emphasizes the electronic components found in everything from suspension control to CD players. Granted, the electronics designed to make important automotive safety and high-tech entertainment features are not as sexy as an interior shot of heated leather seats and a sunroof, but without these features many vehicles would lack the important elements that make them so popular with buyers.

What many people do not know is that ceramics, and specifically ceramic passive components, are used with great success in automotive electronics. They do not realize that ceramics, some smaller than the tip of a pencil, can be used in automotive electronic applications. Even within the automotive electronics world, ceramic passive components are not always top-of-mind. Although 60% of automotive passive timing devices are made from ceramics, engineering textbooks barely mention their role in vehicles.

However, things are beginning to change. Ceramic components have become exponentially more sophisticated while their size continues to decrease. Further, automotive-grade ceramic passives can now be developed in large quantities, reducing their cost while offering similar-and in some cases improved-characteristics when compared to alternative materials.

In addition, as automotive safety, communication and entertainment applications become more complex, the ideal properties of ceramic components help make these new products possible. Ceramics are also paving the way for the next generation of vehicles, hybrids and other eco-friendly cars and features. Therefore, advanced ceramic components, with their low cost, small size, improved reliability and ability to meet the stringent demands of the automotive environment, are making important strides in this market.

Ceramics Make Automotive In-Roads

Prior to World War II, the technology to turn ceramics into passive components was lacking. Electronics found in products like televisions mostly consisted of vacuum tubes. Cars were using electronics, notably in radios, but ceramics were not a part of the design.

The situation began to change after the war, when companies experimented with new ceramic manufacturing techniques. By controlling materials at the molecular level before processing, molding and firing them, ceramics with unique electric characteristics could be developed. Ceramic materials like barium titanate and lead zirconium titanate (PZT) were manipulated to produce components that, among other things, store electrical charges and protect currents from excessive voltage. Soon ceramic components like filters, capacitors and inductors were being used in a variety of products, including household appliances. Ceramics were also made for consumer radios, but nothing was developed specifically for automotive applications until later.

During the 1970s and 1980s, cars started to host more electronic elements. New radios, 8-tracks and tape decks were in demand. Entertainment features normally found in homes were making their way to cars. Companies that already made components for consumer audio needs recognized that a new market existed for automotive electronics.

The 1990s ushered in another trend that would make an important impact in the automotive world and also necessitate the need for more electronics-the advent of safety features. Air bags and anti-lock brake systems were just beginning to come into favor. Today, cars offer even more safety features due to Federal regulations and public demand. In fact, automotive electronic purchases for cars have transitioned from mostly entertainment-based applications to safety features.  

Automotive Ceramics Today

Today, ceramic passive components can be found in almost every aspect of a vehicle. Aside from air-bags, safety elements in cars now include tire pressure monitoring systems (TPMS) that warn of unsafe tire pressure, and back-up detection, which alerts drivers to obstacles near the rear of the vehicle when reversing. Blind spot detection is another beneficial safety feature. One of the main reasons why ceramic parts are now considered for these features is that the improvements made at the molecular level have increased performance reliability in automotive environments.

For example, most automotive safety applications need timing devices to work. Crystals were traditionally used, but now more rugged and robust ceramic resonators can replace them. In addition, the less-expensive ceramic component provides a faster start-up time (related to frequency tolerance). The biggest change for ceramic resonators is the vast improvement in total frequency tolerance over the past 20 years, allowing for their use in all modern CAN-BUS applications.

Ceramics have been used in cell phones and other cordless products since their inception, and are a perfect fit for wireless automotive technologies. Components for electromagnetic interference (EMI) and microwave applications are now in vehicles, while Bluetooth is being heavily touted for hands-free features. The electronics behind remote keyless entry (RKE) also include ceramics. In short, everything from navigation systems to satellite radio utilizes capacitors, EMI filters, bandpass filters and numerous other baseband and microwave components that are derived from ceramics.

Advancements have also ushered in new automotive technologies. In hybrid vehicles, capacitors need to protect against charging circuits from voltage spikes that occur when a car switches from gasoline to battery power. Ceramics are best suited as snubber capacitors because they are smaller than electrolytic and film-based capacitors, are non-polarized for easier application, and work at 125ºF and higher.

The Future of Automotive Ceramics

As cars become more reliant on electrical systems for safety, entertainment and mechanical aspects, ceramic passive components will continue to impact automotive electronics and increase in demand. Some of the rise will be attributed to additional government safety regulations requiring new electronic safety devices, but changes within the general electronics market and further improvements to ceramic materials will also play a role.

For example, the trend within the electronics market of modulization (where individual active and passive components are combined together on a miniaturized substrate) will also emerge in automotive electronics. Vehicle makers and electronic suppliers are becoming less willing to spend the time required to develop discrete solutions for existing and potential wireless connectivity applications, such as Bluetooth, WiFi and WiMax. Modules, especially those using ceramic substrates with embedded passives to minimize the footprint, will allow engineers more time to design and focus on the value-added functions of budding wireless technologies.

Wireless features promise to be popular, especially with the addition of WiMax technology, which will be used not only for entertainment applications but for traffic control and enhanced navigations options, just to name a few. Again, ceramics lend themselves well to automotive wireless features because of their small footprint, low cost and ability to withstand the harsh environments.

Moving forward, an emphasis on research and development to further upgrade ceramic materials will increase the popularity of ceramic-based passive components for this market. Chemical constitution, the form of material particles and grain size control technology at nanometer levels are all being studied in an effort to further reduce the size of ceramic passive components while increasing performance and reliability. Crystal formation firing times and temperature profiles are also being considered, since changes in these elements greatly affect electric properties such as a ceramic’s ability to withstand voltage.

The beneficial properties of ceramics and persistent improvements to their design and structure are changing the way automakers are thinking about how these miniature-yet-reliable components can be used in vehicles. No longer taking a back seat to tantalum, quartz crystal and other materials, ceramic passive components will continue to make a positive impact on automotive electronics and will only increase their presence in this ever-evolving market.

For more information regarding the use of ceramic components in the automotive industry, contact Murata Electronics North America, 2200 Lake Park Dr., Smyrna, GA, 30080-7604; (770) 463-1300; fax (770) 436-3030; e-mail ptiller@murata.com; or visit www.murata.com.

Links

• Murata Electronics North America