Thursday, October 20, 2016
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Higher Performance Connectors Meet Stressful Applications
A large variety of connector types have traditionally been used in electronic designs. regardless of size and weight.

Rapidly changing demands and designs in product performance and electrical integrity are having effects on electronic connector systems. Connector requirements and designs are changing with smaller and more portable electronics designs in aerospace, defense, and other stress-filled environments, such as those already encountered in robotics and oil exploration applications. To meet these growing needs, changes are needed in standard micro-D connectors. New technology, including new latching Micro-D connectors developed by Omnetics Corp. (, offer significant improvements for rapid connection and release with proven signal integrity for the growing number of portable and ruggedized electronics applications. This new latching connector technology provides performance rated to high shock and vibration levels and tested at military-grade specifications.

Electronic instruments are rapidly evolving, with increasing functionality in smaller physical sizes. Newer electronic instruments can afford neither the space nor the weight required by older cabling and connector systems. Traditional connector types have not often been designed with considerations for small size and light weight.

Even many of the older military specification models are rapidly becoming outdated in the face of evolving demands for smaller and lighter interconnection systems. Older connectors like the D-subminiature connectors (MIL-DTL-24308), requiring 0.100-in. from pin to pin, just do not fit within today's electronic systems. Rapid industry growth in microsize connectors with 0.050-in. spacing and nanoconnectors with 0.025-in. spacing are fulfilling the needs in today's higher-technology electronics applications.
The new Latching Micro-D connector technology brings quick-change design opportunities to a number of different applications.

Many industries are undergoing changes as they experience the benefits of rugged portability and miniaturization and adjust to new connector and cable designs. For example, a number of military and deep-space applications have explored the use of robotics technologies and then emergency rescue device development companies began using miniature cable and connectors. Then, since many emergency applications require the use of devices that can run at higher temperatures, to +200°C, petroleum research and geothermal industry equipment developers looked at higher temperatures for their equipment designs and started testing new micro-D connector technology for their applications.

This trend in higher integration within smaller electronic equipment spaces is growing across many different industries, with micro-D connector technology providing a means of achieving the higher levels of electronic integration. Electronic designers are heralding the ruggedized miniature connector as a major solution to a combination of design needs and application-related demands. The trend also includes a need for quick plug-and-release connector technology, because users prefer not to require additional tools to mate or release a connector.

Increasing Complexity
As electrical circuit technology and complexity evolve, chip speeds are increasing and their data rates are rising, with currents and voltages being used at lower levels and mixed-signal systems demanding the same interconnect systems. The use of these new circuits with higher circuit speeds are evident nearly everywhere, but are most critical in surveillance cameras and high-resolution displays in portable military applications, space satellites, and ruggedized robotic equipment.
A number of different cable types have been used to prevent signal instrusion.

Miniature electronic modules are moving from big-box, out-through-cabling designs to probes, sensors, and detectors that deliver a variety of information to a main unit, including video, thermal measurements, shock, and guidance data. Circuits in mission-critical applications are often placed in harm's way and must maintain the highest reliability and signal integrity even in stressful environments, including high shock and constant vibration.

Changes in electronic components and applications have allowed and demanded significant changes in the systems that connect each electronic module to the main unit, such as cables and connectors that assist in interlacing electronic connections from module to module or module to sensors, detectors, cameras, lasers or other data acquisition or data distribution devices. In many cases, new electronic designs must be rugged and reliable, wearable or portable, and meet the standards of a system in motion.

A number of critical elements have changed in both the application and design of those interconnection systems serving new electronic products:

  • Voltages are somewhat standardized and are significantly lower than before.
  • Current levels are dropping to milliampere levels, compared to older electronic systems.
  • Space for signal routing is limited.
  • Connector and cable weights must be reduced to increase the service life of the electronic module.
  • Ruggedness is increasingly significant, especially in airborne and robotized instruments.
  • Rapid connect and interconnection is often critical for in-field applications.

Industry trends have shown that most cable and connector manufacturers are rapidly tooling smaller interconnect systems to meet the mechanical and physical configurations that can serve the requirements of modern miniaturized and ruggedized electronic products. Electronic design groups are also pushing new limits in providing faster and more efficient microchips. Expanded silicon CMOS technologies have combined many different electronic subsystems within a single chip design. These new chips handle higher-speed signals, process larger memory sections, and operate on lower voltages and lower current levels, greatly extending the battery and field life of the instruments they are supporting.

Analog vs. Digital
Another interesting trend in today's electronic design is that analog signal management is giving way to digital signal processing. Analog signals are not going away; they remain very useful in certain level-sense control and modulation circuits, but they often require cabling with larger wire diameters and at higher voltages.

Digital signal processing (DSP) appears to be eclipsing many areas of electronic circuit design, and is being applied from commercial communications applications (such as cellular telephones) to high-level military and space-technology applications. Digital signals can be easily routed and managed, and even boosted in speed with lower cost and complexity in the electronic configurations.

Higher-speed digital cables often employ a differential pair of twisted wires, such as Apple's FireWire cabling. By using small-diameter cables, high-integrity, high-reliability signals through the Gigahertz range can be transferred. This trend of increasing electronics in smaller sizes is opening the way for new electronic products in portable and rugged applications. Another advantage of DSP within cabling is the security from listening devices that is much greater than with analog signals. The digital cabling is more secure since the cables can be shielded and protected from detection well beyond what is possible through the airwaves with radio transmissions, especially when confidential information must be kept secure.

Latching Micro-D Connectors
Micro-D connector technology has been in use for generations. It is a smaller type of connector derived from the D-subminiature or D-sub (named for its D-shaped metal shield). The microminiature-D or micro-D connector is about one-half the length of a D-sub connector, and has proven to be extremely successful over the last 40 years.

Recently, Omnetics developed a new Latching Micro-D connector to retain the advantages of the popular and proven micro-D design and update it to meet the requirements of smaller and more mobile technologies. These mobile technologies tend to require more-frequent module changing and rapid field replacement of modules and systems in places where additional tools may not be available or practical. Digital signals from optical surveillance systems, low-voltage differential signals, and even lower-current power supplies are some of the newer applications taking advantage of quick-change opportunities afforded by Latching Micro-D connectors.

The new technology is based on the micro-D configuration's well-established reliability and performance specifications. It also takes advantage of known voltage and current ratings and the fact that it can be adapted for many board-mount, panel-mount, and wiring configurations and pin counts. The new Latching Micro-D system has three major sections or components. Wired plugs are connected to cables or open wiring that includes optional metal or over-molded back-shells for electromagnetic-interference (EMI) protection, and a strain-relief design that reduces wear on the cable interface to the back shell of the connector.

The Latching Micro-D connectors support a wide range of cable types that can include open wiring, jacketed cable sets, and even EMI-shielded braided coverings to protect signal intrusion and/or signal noise from escaping the cable and affecting other circuits.

With the latch design, the cable can be quickly disconnected in a simple squeeze-and-pull motion. An adapter can be added to existing micro-D connectors to allow current instruments to use the latch on cables in their system.

The connectors are built with rugged and compact designs using aluminum alloy 6061 shells with nickel plating, with contact counts from 9 to 51 positions. Based on a one-piece beryllium copper flex pin design, the connectors are plated with nickel/gold for use from -5 to +125°C, with a special version rated for temperatures to +200°C. The Latching Micro-D connector's high-reliability, light-weight, rugged, quick-connection system has enabled a number of newer miniaturized equipment designs. Cable systems include braided shields to reduce EMI and cross talk. Adaptations to older jackscrew designs can be accomplished by adding a simple "latching adapter" to existing micro-D connectors.

As new electronic products are developed for more portable and rugged use, miniature micro-D connectors are helping to meet demands for limited capacity and weight. Matching cable and wiring systems are available and can be implemented immediately, without needs for adjustment or design changes. Designers can even use standard solder-cup versions of these connectors in their own laboratories for prototyping and circuit development. The quick-connection capabilities also help speed the test-and-analysis process.

Contact: Omnetics Connector Corp., 7260 Commerce Circle East, Minneapolis, MN 55432 800-343-0025 or 763-572-0656 Web:

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