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CIRCUIT PROTECTION & ENCLOSURES resistance (i.e. better clamping). In this particular case, the High-Speed USB could function with approximately 1-2 picofarads, but the customer’s target was less than 1pF to ensure maximum signal integrity. On top of that, this target came along with a request for a low dynamic resistance value more customarily found in products with 15 to 20pF of capacitance. The new solution required the use of proprietary silicon processing and silicon design techniques. It proved to be advantageous that the customer was able to meet with its component supplier at its manufacturing site in China to see how they perform testing and how their components interact with the overall system. This provided them the opportunity to gain a better understanding of the relationship between and the performance of an individual ESD component and overall system ESD immunity. The SP3031 is now in mass production, shipping since the end of 2013. Knowing that 2015 model televisions will require a higher level of ESD immunity (possibly 6kV), Littelfuse is already working on designing a new protection component to meet this requirement by further lowering the dynamic resistance to obtain a lower clamping voltage and at the same time maintaining low capacitance and signal integrity in the system. Looking at this case study, we could conclude that preserving a smart 60-inch screen from ESD depends on 0.6mm2 of silicon. Form-in-place thermal gap filler has a thermal conductivity of 4.0 W/m-K Gap Filler 4000 from Bergquist is the company’s latest dispensable thermal interface material, combining a thermal conductivity of 4.0 W/m-K with an extended working time of up to four hours for greater flexibility in dispensing and assembly processes. The two-part liquid material has shear thinning characteristics for optimum dispensing, and displays excellent wetting with ultra-conformability to minimise stress on components during assembly. Designed for filling unique and intricate air voids and gaps, the gap filler remains in place after dispensing and maintains its shape on the target surface. It has a low level of natural tack, and is intended for applications where a strong structural bond is not required. Cure time is 24 hours at room temperature or 30 minutes at 100°C. Bergquist www.bergquistcompany.com TVS diodes provide ESD protection to fast links Infineon Technologies’ ESD105 series of Transient Voltage Suppression (TVS) devices protect high speed interfaces of electronic systems from Electrostatic Discharge (ESD) strikes. Designed with miniaturized integrated packages for mobile devices, the ESD105 series addresses TVS for high-speed data interfaces, such as USB 3.0, Gbit Ethernet, Firewire and HDMI links used in desktop computers, TV sets and portable electronics. Being located at the surface of a device, these interfaces are especially sensitive to ESD. A mere touch of the hand can be sufficient to induce an electric current, and the energy generated by the discharge can damage the equipment or even render it completely unserviceable. With very-low clamping voltage (10V at 8kV) and ultra-low capacitance (C = 0.3pF) the ESD105 TVS diodes (single line) enable engineers to achieve strict requirements for ESD robustness and signal quality of the high-speed interfaces used in the latest generation smartphones and tablet computers. The new series provides protection that exceeds the specifications of IEC61000-4-2 in 2-pin packages (0201, 0402). The leakage current is under 20nA, contributing to longer system battery life. A dedicated pad-layout keeps PCB layout simple and minimize parasitic effects. Infineon www.infineon.com/tvsdiodes Reinforced elastomer seals maintain surface electrical continuity at joints Chomerics Europe’s Cho-Seal range of reinforced moulded elastomer seals are available in either conductive or non-conductive formats and are designed for use in applications such as airframes to provide EMI shielding, lightning protection, HIRF protection and radar cross-section reduction. They maintain surface continuity at joints, seams and openings in air frames. The reinforced elastomer seals consist of a corrosion resistant elastomer base with an integral woven or knitted fabric or wire mesh which gives excellent mechanical properties that allow the seals to be used in the most demanding applications. Depending on the requirements of a specific application, Chomerics can use any one of a number of its corrosion resistant silver plated aluminium and silver plated nickel filled standard Mil/Aero silicones and fluorosilicones as the base material. Knitted Dacron fabrics dramatically increase the tensile strength of the elastomer without adding weight to the seal. For applications where high current carrying capability is required, for example to provide lightning strike protection, aluminium or wire mesh can be used. If needed other reinforcing materialscan be used to give characteristics such as flame resistance. Chomerics www.parker.com 44 Electronic Engineering Times Europe March 2014 www.electronics-eetimes.com


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