Feature Interconnection
On active service T
Alec Sluce, connector Product Manager at Aerco, discusses what’s required to stay up to speed with interconnection in the defence industry
o remain successful in supplying interconnect solutions to any sector, manufacturers and suppli- ers must be ready to react quickly to changes in customer demand. In the commercial and consumer electronics market how we live and work creates rapidly changing demands on suppliers to continually develop new products. The same forces are at work in the defence industry.
Soldiers now carry more electronic equipment than ever before and there- fore there is a requirement for smaller, lighter equipment that, in turn, demands smaller and lighter connectors combined with enhanced capability. To provide lightweight connectors that are environmentally sealed to IP67, protected against EMI, mechanically robust and easy to mate and un-mate is the driving force of connector manufac- turers who target the defence market. As an example, Hypertac, now part of Smiths Connectors, responded to this demand by merging two contact technologies to form its SnapTac range; a miniature connector capable of hold- ing up to 19 contacts in a high perform- ance push-pull connector that has a highly resilient interconnect system. This range utilises the company’s Hyperboloid contact design with the mechanical features of a spring-loaded contact to produce HyperSpring. The key innovation is that the spring plays no part in conduction of electricity, leaving this to the Hyperboloid contact, so it can be chosen purely on its mechanical performance, namely its elasticity. This optimises the physical performance of the system to an extent that 10,000 mating cycles can be achieved.
Despite the RoHS initiative, cadmium-plating remains the domi- nant finish for connectors in the defence sector because of its excellent salt spray performance coupled with a high degree of electrical conductivity. Although the industry has tended to resist moves from cadmium towards lower performance, RoHS compliant finishes zinc-nickel, a finish that passes the 500 hour salt spray test while maintaining a shell to shell continuity of less than 5milliohms, is gaining popularity and is now specified in a number of key military vehicle programmes.
20 Rugged computing
The Defence industry is one of the biggest users of rugged computing devices. In the field, a whole range of data on situational awareness, logistics, inventory and maintenance plus other vital information is gathered from numerous sources and has to be inte- grated and disseminated quickly. RJ45 and USB connections, widely used in the commercial world, are now available in products such as the ABAC range from TTAB Connectors and the Glenair Sureseal connectors housed in rugged military shells based around Mil-DTL-38999 and MIL-DTL- 26482. This makes them suitable for military applications and the combina- tion allows for harsh environment interconnect for Ethernet Cat 6a with transmission speeds of 10Gb/sec. Increasingly though, even laptop computers are seen as too large and heavy for fast moving military forces and are making way to rugged handheld tablets and even mobile phones. These in turn require ever smaller interconnect solutions that force the adoption of suitable COTS connectors that do not comply to military specifications. As demand increases for miniaturi- sation so connector manufacturers need to find ways to increase contact density while maintaining performance levels at high frequencies. Hypertac’s Tortac system provides a socket with an external diameter of 0.8mm thus providing a pitch of 1.27mm and a contact density of 60 ways per cm
2 .
This has proven successful in a number of radar applications but the pressure continues and the company is now working on a 0.55mm diameter socket.
Figure 1: Hypertac HBB connectors from Aerco ideal for unmaned vehicles
Board to board interconnect With the emphasis on miniaturisation and the perpetual quest to reduce size and weight, PCBs are now smaller and stacked much closer together and this has led to the introduction of a new range of inter-board connectors. Products such as the Hypertac HPH connectors have double the contact density compared to those of just a few years ago while the HDLP is a range of low-profile, high density, rectangular, surface-mount PCB connectors designed specifically for missile guidance and propulsion systems, ruggedised computer systems, cameras, display systems, communica- tions panels and enclosures and other military applications.
The MLPI (Microminiature Low Profile Interposers) also from the company are a new range of spring- loaded, high-density connectors that uses contemporary contact technology to provide a spring-loaded contact system allowing one PCB to be connected to another situated directly above it. With this design there is no appre- ciable degradation of contact resist- ance over a long life cycle or low variation of electrical contact resistance even under extremes of shock and vibration as a result these connectors are ideal for space constrained designs and for where high-performance remains essential such as in board-to-board stacking assemblies in defence electronics or other demanding applications.
Power distribution
Background image: Hypertac MLPI connectors from Aerco
Alec Sluce is
Connector Product Manager at Aerco
Aerco
www.aerco.co.uk Enter 206
As the number of on-board systems continues to increase, the need to achieve power distribution via a mini- mum number of interconnects is a major consideration for military equipment. All the main connector manufacturers are now promoting their high current capability with con- nectors capable of handling 300, 500 and 750A becoming commonplace. The Hypertac HBB series gives the required power capability and mechanical endurance of over 2,000 mating cycles achieved with no concession to weight or size. The pressure on manufacturers to meet more demanding technical speci- fications while meeting exacting military regulations will inevitably continue. It is the responsibility of manufacturers and distributors targeting the defence sector to form effective partnerships to bring this new wave of connector products to the market in good time and at a price that is acceptable in the present economic conditions.
NOVEMBER 2013 Electronics
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