As analog circuits gave way to digital circuits and electronic devices shifted from wired to wireless connections, overall device design is moving from desktop to portable. With this trend towards portability, system durability has become extremely important.
System design engineers have begun designing and constructing pre-tested modules, then using this as a primary construction technique to stack or blind-mating them. This necessitates nanoscale interconnect devices. Manufacturers in the medical and aerospace industries are driving systems towards this modular direction to meet the size, weight, and current requirements of complex signals. To address these challenges, new connector designs must accommodate the combined requirements of enhanced electrical performance and durability while reducing the size and weight of interconnect systems.
Size and Weight Advantages
Improved machining, molding equipment, and materials have enabled further structural reductions in connector size. While both dimensions and weight meet MIL-PRF-83513, a 21-bit nanoscale connector weighs only 0.4g, compared to an equivalent miniature D-connector weighing 2.60g. Furthermore, a 37-bit miniature D-type connector requires four times more space than a 37-bit board-mount or PCB connector.
Design and material selection are key to successful size reduction. At the heart of the design is the flexible pin. To achieve high contact strength, low contact resistance, and maintain performance through thousands of mating cycles, beryllium copper with special tensile annealing properties is required. The key specifications of beryllium copper thickness, length, and shape ensure long lifespan and sustained performance of the miniature connector pins.
The insulating shell is mostly made of injection-molded liquid crystal polymer; some older designs used polyphenylene sulfide. When a 0.025" pitch results in only 10-11 mils of insulation between the pins, this type of insulation material still exhibits high retention and high electrical insulation strength. High-reliability pogopin connector bodies can be made of insulation materials used in insertion and low-vibration applications, but most high-vibration and high-shock applications require a metal housing.
Durability and Reliability
Durability depends on good mounting design. Force and acceleration are key factors in testing the strength of pogopin connectors in harsh applications. Due to a well-designed mounting bracket, nano-sized pogopin connectors can withstand vibrations and shocks exceeding 10,000 Gs, such as under fire and firing conditions.
Nano-circular Connectors
Compared to nano-sized circular pogopin connectors, miniature circular connectors (0.050" pitch) are significantly larger. When using 0.025" pitch pins and sockets, up to four times more interconnects can be used in the same circular area. Newer circuits typically require current less than 1A because digital processing allows for smaller wire gauges within the cable assembly to accommodate nanoscale circular connectors. This significantly reduces the overall weight and diameter of the interconnect system. An additional benefit of nanoscale cables is increased flexibility, as smaller diameter cables are easier to route in constrained locations.
Depending on the application, nanoscale circular connectors come in various types. Metal-cased nanoscale circular connectors offer the highest durability, excellent strain relief, and a handle mechanism. They feature 360° sealing rings for shielded cables and environmental seals to protect against immersion. Typically, they are used to connect remote detectors, sensors, and instrumentation to the front panel of equipment. Nanoscale circular connectors are either molded or mounted into the system engineer's own instrumentation. This approach saves considerable space and allows the device or detector to have its own complete set of motor and mechanical connectors.
Other Solution Product Structures
Modules are uniquely shaped and, in some cases, move or rotate continuously. Microrobotics, servo systems, rotary systems, and oil drilling all involve highly sophisticated electronic components. These modules are positioned near the functional operating areas of the circuitry to ensure optimal signal performance.
Conventional wires are generally too large, too stiff, or even too expensive to install. New computer-aided design systems can quickly simulate nanoscale flexible circuits to accommodate dense points. High-density, low-duty-load flexible nanoscale connectors have become an important solution for many challenging designs.
As module functionality increases, the number of wires they control is also increasing. The number of pins is also increasing. At one end of the module's cable, micro-connectors solve many size and weight issues.
However, the sensor end or board-to-board interface end of the system often requires even higher density interconnects. The solution is micro-nano cables or flexible systems. High-contact, high-extraction systems using micro-connectors ultimately connect to high-density 0.025" pitch nanoscale connectors at the other end.
Conclusion
Miniaturization, lightweighting, and demanding applications are on the rise. Digital electronics, high-speed transmission systems, and small robots all require increased density and circuit count. Currently, numerous applications of nano-miniature pogopin connectors include unmanned spacecraft (UAVs), displays, and missile guidance in the aerospace industry; magnetic resonance coils, surgical drills, and digital stethoscopes in the medical industry; and navigation for communication satellites, Mars rovers, and space shuttles in aerospace applications.
Nanature pogopin connectors have already proven their effectiveness in aerospace applications. Furthermore, they are already serving the medical and oil industries and are entering a wide range of portable and remote-controlled products. New designs are enabling nano-miniature connectors to replace micro-connectors; for example, high-density nano-circular connectors are replacing many larger micro-circular connectors. Circuit and board designers will thus have broader horizons, and nano-miniature connectors help achieve their goals.
