In-Car Interconnection Systems Evolve to Meet New Challenges
By Andy Kotas, AVX/Kyocera Connectors

Once limited to high-end luxury models, in-car electronics systems are now increasingly appearing across the full spectrum of vehicles. Consumers are highly interested in vehicles that have built-in technologies, such as GPS and telematics systems, audio products, steering wheel controls, climate adjustment, and mirror and set positioning.

However, the increasing use of electronic products inside the automobile is putting pressure on systems makers, and on the design practices and components they use. Reliability and miniturization are two key issues. Also, the constant changes in the technology arena requires agile system redesign capabilities to respond to market demands and product innovations. For example, Europe and many states in the U.S. have banned the use of handheld cell phones while driving. This has rapidly expanded the use of Bluetooth and other hands-free systems. Interconnection systems specifically designed as interior automotive applications, such as multimedia and dashboard systems, have helped engineers achieve these new system and application requirements.

Other factors impacting designers come from the application environment. All electronic components used in automotive applications must be able to withstand harsh environmental conditions, such as shock, vibration, and heat. Connectors designed for use in laptops or cell phones will not be able to perform under normal conditions that are routinely experienced by products used in the automobile. This is especially true when we consider that such devices must be miniature, fine-pitch devices, as space inside the vehicle is at a premium.

Forty years ago, vehicle dashboards only had a few, basic instrument gauges. Today’s vehicles feature dashboards that surround the driver and passengers with a plethora of gauges, information, and entertainment displays. For these reasons, interconnection systems used for interior automotive applications, such as multimedia and dashboard systems, are moving away from discrete wiring solutions to flat flex cables and micro connectors with secure, reliable locking designs.

Connector miniaturization has a very large impact on the assembly processes. Traditionally, connector assembly and wiring harness production has been done manually. However, when cable diameters shrink and pitches become ever more fine, the length of time it takes to manually assemble discrete wire connectors increases, and eventually it becomes impossible to guarantee quality—another pre-requisite of the automotive industry.

Therefore, connector manufacturers have complemented their ranges of discrete wire solutions by developing special miniature components designed to enable flat flex cables to be securely connected in one simple action. The drive is to provide greater security than standard parts and to facilitate semi-automatic, and in some cases, fully-automatic production processes. These low-profile FFC/FPC connectors feature a secure locking mechanism, making them ideally suited for products with displays—audio/visual devices such as DVD and satellite navigation screens, as well as digital speedometers, tachometers, and rearview mirror displays—and require a long life. They are designed to eliminate production process failure, prevent accidental removal of the cable in the field, and withstand the levels of vibration and temperatures common to automotive applications. Moldings in the connector accept shaped FPC/FFC cable and lock to guarantee that accidental removal of the cable and incorrect insertion is virtually impossible. Furthermore, the shaped cable ensures correct alignment in the production process, eliminating failures due to misalignment. To facilitate ease of assembly, a one-touch flip-lock provides audible and tactile “click” feedback.

For example, AVX’s 6288 series ZIF connector family features small 0.5mm pitch connectors, available in eight through 60 positions, with a current rating of 0.4 amps/pin; voltage rating is DC to 50 volts. The 2mm high connectors are tested to automotive specifications and rated for the extended -40°C to 105°C temperature range. The standard 0.5mm pitch contacts feature a gold-flash finish that helps to prevent solder whiskers, leading to higher reliability. Devices are lead free and RoHS compliant. The connector manufacturer is continuing to develop the secure locking theme in its fine pitch connector range, adding a 1.0mm pitch version to the product family later this year. To give full flexibility to the automotive electronics designer, AVX is developing a new vertical type locking FFC/FPC connector, targeted for release before 2011.

To cope with higher data speeds—and the desire for “always on” media and Internet access—connector manufacturers have created right angle mount products capable of handling higher speed signals for use with impedance-controlled FFC cables. Vertical versions are scheduled for release next year. With speeds of up to 3Gb/s and specifications tailored towards the automotive industry, they complete the lineup of FFC/FPC products.

Moving even further away from discrete solutions, the automotive industry is embracing formats such as the SD Card. There are special considerations to take into account when bringing this technology to the vehicle cabin. One of the main problems encountered with media cards is the possibility of inserting the card incorrectly into the connector. Damage to the connector can lead to expensive re-fits of the whole infotainment system. Manufacturers have designed connectors specifically to reduce the damage caused by wrong insertion to meet the needs of automotive manufacturers.

The automotive industry has moved a long way from the time when cars were essentially a mechanical product. Today’s consumers expect much more than just a means of getting from point A to point B. The interconnect system is one of the most vulnerable yet vital parts of the automotive electronic systems, thus spending the time to select the best performing and most suitable connector for modern production processes is essential.

Andy Kotas is the marketing manager for AVX/Kyocera Connectors. He can be reached at kotasa@flt.avxeur.com, +44 (0) 1252 770074, or www.avx.com.