Posted by John McHaleST. AUGUSTINE, Fla., 14 May 12 2010. Carlisle Interconnect Technologies, Jerrik Division announced a new avionics printed circuit board (PCB) for transient voltage suppression (TVS) filter connectors that incorporate the TVS diodes directly into the PCB. The new design enables military and aerospace avionics suppliers to design electromagnetic pulse and lightning protection into their modern equipment while using less space and weight than a conventional filter connector.Previously the TVS diodes were clustered around the PCB in a cordwood type arrangement, Carlisle officials say. This new development in PCB design creates a TVS filter that is more compact, lighter in weight, costs less and is quicker to manufacture. This patented design for diode packaging can be used in several applications including military aircraft, commercial aircraft, and helicopter environments.The ideal location for diodes to act as TVS devices for modern avionics boards and boxes is inside the interface connectors. When considering the higher density multi-pin connectors commonly used, finding the room to package these diodes is a challenge.Often the connector industry makes use of leaded diode devices mounted into the PCB to meet this challenge. The result is known as cordwood stacking of the devices around the periphery of the connector contact pattern. In other words, for a 25 pin connector, the center of the connector would house the standard 25 contacts while additional space and weight would be added to the outer edges of the connector to house 25 individually packaged leaded diodes. Often this cordwood connector is double in size of a non-TVS equivalent. Depending on the screening level specified for the diodes, lead times and costs for the diodes could be excessive.CarlisleIT Jerrik's solution to the size and weight issues is mounting the diodes in die form directly into the PCB adjacent to the contacts that they protect, company officials say. In even in the densest arrays CarlisleIT Jerrik can place a diode next to every pin, assembling the finished connector using the same proven designs employed in conventional filter connectors. Also, with a little more shell length, CarlisleIT Jerrik can include an electromagnetic interference (EMI) filter array in the same package. By using this concept of embedding the diodes within the PCBs the designer can make use of tighter packaging and off-the-shelf dies to create a connector that matches the size of EMI filter connectors, company officials say.
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