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‘Chip-on-flex’ simplifies a/c lightning protection

 - June 16, 2009, 7:13 AM

ITT Interconnect Solutions has enhanced its chip-on-flex (CoF) filter connectors with TVS surge suppression capabilities using chip capacitors surface-mounted on a small pad adjacent to the feed-through contact.

“As the aircraft industry strives for robust protection from lightning strikes, EMP and voltage surge for its sophisticated electronic systems, the role of interconnect devices at providing protection from voltage spikes becomes imperative,” according to the company.

“The flex circuit design provides the necessary platform to surface-mount TVS devices for lightning-strike protection. This allows us to mount off-the-shelf devices for both filtering and surge protection using automated manufacturing processes,” added director of marketing Keith Teichmann.

According to the Santa Ana, California-based company, transient voltage suppression in interconnects is typically accomplished by attaching a device that shorts voltage spikes to the connector shell [but] true protection may be provided only by attaching a “transorb” to every contact. This is labor intensive and costly.

The ITT design replaces the fragile ceramic planar array block capacitor that is usually required with a patented flexible circuit where individual chip capacitors are surface mounted on a pad adjacent to the feed-through contact. Since the feed-through contacts are not soldered directly to the capacitor, “stress points that impact performance during thermal shock and vibration have been virtually eliminated,” said the company.