Ulti-Mate Connector has released the following article outlining the use of micro- and nano-miniature interconnect solutions for rugged applications and extreme environments, such as the operating conditions experienced by UAVs (unmanned aerial vehicles), UGVs (unmanned ground vehicles) and other robotic systems.
Connector and cable decisions are often postponed until the final stages of electronic engineering design, when decisions must be made about how best to interface the balance of the circuits and additional boards and equipment included in the new design. This approach may leave the designer with little or no board space to place the necessary connector(s). Understandably, design teams are more concerned with seemingly more important elements of their projects, such as processing, imaging, and motion, and commonly neglect the more mundane process of connecting board to board, or getting signals to and from their devices. Every link in the design chain is as critical as the next. Longer lead times need to be considered, and choosing an inadequate interconnect system may cause a system to fail just as fast as a failed circuit, sensor or processor.
Design factors and application conditions
Factors that must be considered in connector design include current carrying capacity, voltage requirements, temperature ratings, available board space, and environmental concerns. Design durability must also be considered, including the expected number of mating cycles, handling conditions, and the intended users of the connector, who may include lab technicians, military personnel or oil exploration workers.
New applications in diverse fields, such as drones, munitions applications, robotics, and medical electronics require miniature yet highly reliable, rugged and durable connector systems. There is also increased need for high-density connectors that are capable of withstanding the harshest shock, vibration and temperature conditions.
Many commercial high-density connectors commonly used in small portable electronics are too delicate to survive such demanding environments.
Micro- and nano-miniature connectors
Basic physics provides a surprising yet logical explanation of the durability and reliability of micro- and nano-miniature connectors. According to Newton’s second law of motion, Force = Mass x Acceleration. Therefore, a lighter, lower mass connector will withstand greater acceleration (which in harsh environments may arise due to shock) than a heavier interconnect if both are given equal force and good design.
Micro connectors defined by MIL-DTL-83513 on a .050” pitch are 4 x smaller than a MIL-C 24308 D Subminiature on a .100” pitch. Nano connectors as defined by MIL-DTL-32139, are 4 x smaller than a Micro connector. The pitch of a Nano connector is only .025”, which means it is only a quarter the size and has 80% less mass than the MIL-DTL-83513 Micro D.
Crucial contact design
The performance of micro- and nano-miniature connectors under extreme conditions is largely dependent its contact design. Many designs have been put forward, including twist pins, solid pins, stamped pins and formed compliant pins, all of which comply with the Mil-Spec performance requirements. In spite of the design variances, all of these can deliver a reliable solution, albeit some better than others under certain circumstances.
For further information on the advantages of stamped and formed nano contacts, please read this article on the Ulti-Mate Connector website.
Shock and vibration performance issues
Micro D and Nano D specifications are both rated at 1 microsecond max discontinuity for shock and vibration. These minor discontinuities will not affect performance, including the performance of electronic equipment that is increasingly reliant on LVDS (low-voltage digital signal) technology, where even a small discontinuity can mean that a signal is lost. Use of a Mil-Spec style stamped and formed compliant pin, will not suffer higher discontinuities commonly experienced with other contact designs found in commercial connectors.
Size and weight
As the demand for smaller, more reliable and lighter weight electronic equipment for demanding applications grows, the common MIL-STD 38999 circular connectors can be too bulky and heavy. For similar reasons, traditional rectangular D-Subminiature (MIL-C-24308) configurations are no longer suitable because of their size and weight. High density micro and nano connectors are designed to meet these critical design requirements.
Ulti-Mate Connector’s stamped and formed micro and nano Mil-Spec style contacts are available in a variety of connector formats, including single and two-row strips, latched micro connectors and circular designs, both standard and custom. These connectors can be supplied in complete cable harness configurations based on customer requirements.
For more information on micro and nano connectors for drones, unmanned systems and other demanding applications, visit the Ulti-Mate Connector website.