Logo: OmneticsAs speeds go up and voltages decrease, signal integrity design and management is critical to the functions needed in military and aerospace. Digital signal quality is more often assured by using differential cable design that matches the impedance of the output and/or input system of the processor boards and detectors. Also, proper shield and drain wire interconnections increase accuracy of the system, help ensure appropriate eye-pattern quality of the transmitted signal through the connector and cable assembly, and reduce jitter and crosstalk.

Reduced size, lower weight and ruggedness immediately follow in the list of important specifications to serve the needs of portable ground troop electronics, airborne equipment (such as UAVs) and in military satellite systems. Military connector designers must seriously plan and implement the use of military pin-to-socket elements that exceed the minimum requirements of wear during insertion and retraction force.

Figure 1. Latching Nano-Ds. (Photo: Omnetics)

Figure 1. Latching Nano-Ds. (Photo: Omnetics)

More and more, we see demand for ruggedized miniature connectors to enable complicated cable systems to handle very fast and clean digital signals. From high-speed Ethernet to surveillance cameras to portable computers that serve helmets, there is a move to highly mobile military systems. Hand-launched drones and robotic ground monitoring systems all fit into the new push within our upgraded military. Older aircraft are being modernized with higher speed, digital electronic modules replacing older analog systems.

Connector and cable systems are designed differently to serve that new era. Standard micro and nano connectors are often easily modified to meet that demand and adjusted to fit into smaller, tighter spaces within electronic packages. As power and high-speed signals are combined in the SWaP format, we see newer micro circular cables and connectors using hybrid designs that include 3- to 5-Amp pins in the same housing as multiple sets of high-speed digital interconnections. These hybrids span the design range from miniature rectangular to miniature and nano-miniature circular connectors. Performance to the same level as in Omnetics’ older MIL-DTL-83513 and MIL-DTL-32139 is critical in assuring long-range reliability in extreme environments.

Figure 2. Hybrid Nano-circular connectors. (Photo: Omnetics)

Figure 3. Nano-Circulars. (Photo: Omnetics)

Figure 3. Nano-circulars. (Photo: Omnetics)

One example of the connectors being used is the nano-circular breakaway communication connector for pilot use in helicopters. They withstand constant high vibrations and allow immediate release for pilot escape if necessary. A second nano-connector system is being used for flight-control modules in hand-launched drones for surveillance. Micro circular connectors with very small flexible wiring also route digital signal data from ground soldiers’ computers to helmet displays. These rugged devices include both power and up to 3-gigabit-speed digital processing.

A trend is also occurring in military electronic module design: The need is for highly dense packs, as the height of standard micro-D connectors prevents vertical compression and stacking. Low-profile micro-D connectors do much of the same work and are significantly lower in height. They also withstand higher sheer shock and vibration for portable applications.

Figure 4. Low profile micro-Ds. (Photo: Omnetics)

Figure 4. Low profile micro-Ds. (Photo: Omnetics)

When selecting connectors and cables, system-to-system engineers should carefully review the distance from one box to the other and help manage the distance. Planning for electromagnetic interference (EMI) protection that ensures clean lines without noise or cyber intrusion is important. For those working within systems, close proximity can breed crosstalk and skew that will affect signal quality. Mechanical mounting on boards should be tight and clean. New latching micro and nano connectors can help with mating and non-mating.

Methods for Selecting the Right Connector for Applications

System designers can consider at least two options for making a connector selection that matches their application. These methods are based on working with military-qualified suppliers that use subparts and elements that have passed QPL within their standard military connectors.

Option 1

  1. Visit your connector supplier sales team to review current standards that meet or are close to your needs. Collect the specifications of those standards and any rugged test data available.
  2. List electrical signal specifications and discuss signal performance with EE at the connector supplier office.
  3. Chat with the connector designer and get a solid model and dimensions of standards to ensure the fit and function of a standard device.
  4. Compare the above list to standard parts first and ask for a sample.

Option 2

Variations for ruggedness, size and shape can be navigated easily. They also can include hybrid or mixed-signal connectors that reduce the number of cables within a system by adding power-plus signals within one interconnect unit.

  1. Define the variations you need from the military standard connectors available.
  2. Begin modifications, if needed, online with a supplier to build solid models.
  3. When ready, build a 3D model of a customized connector.
  4. When the 3D model looks good, review the planned specs.
  5. Request a first article and specify additional testing to ensure performance.

Finally, the system designer should specify any specific forms of testing and quality assurance that can assure the interconnection systems will sustain high reliability in the rugged and unique environmental conditions of your application.

Learn more about how Omnetics can help with your connector-to-cable design at www.omnetics.com.

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