What are Micro Circular Connectors?

By AJ Born | May 16, 2023

Meet the Connector: Micro Circular

The push to make mil/aero electronic equipment smaller and lighter for easier portability while maintaining its necessary ruggedness requires smaller, lighter, rugged connectors. Enter microminiature and nanominiature circular connectors.

Micro or nano circular connectors feature smaller pin and jack diameters and the pins are spaced more narrowly. This reduces the amount of weight the connector adds to the component and minimizes the amount of surface the connector requires across the face of the terminal.

2M Ram-lock from Amphenol Aerospace

The 2M Ram-lock from Amphenol Aerospace features a positive locking interface and is perfect for applications where accidental unmating is a concern.

The design of the micro circular connector from Omnetics Connector Corporation is heavily influenced by MIL-DTL-38999 Series III and Glenair’s Mighty Mouse Series 805 ratcheting triple-start threaded connectors, said Eric M. Bergquist, project engineer with Omnetics. This ratcheting triple-start threaded connector retains all the benefits of standard threaded circular connectors (3A-rated contacts, space-efficient form factor, possible IP68 rating when mated, outstanding EMI shielding effectiveness, protection of delicate electrical contacts, shock-and-vibration performance, and temperature rating) and two significant additional benefits. Coarse triple-start thread fully mates with significantly fewer turns, improving operator experience and reducing fatigue. It also reduces the likelihood of high-vibration applications shaking the coupling nut loose because the ratcheting action, designed to interact lightly with the coupling nut while mating, resists much more aggressively when de-mating.

Micro 360 ACME Triple Thread Ratcheting Circular metal shell (left) and panel mount connectors from Omnetics Connector Corporation

Micro 360 ACME Triple Thread Ratcheting Circular metal shell (left) and panel mount connectors from Omnetics Connector Corporation are available with metal housings giving them an environmental seal. They have ability to withstand high shock and vibrations while maintaining electrical integrity. A variety of shell material and finishes are available. Sizes: 05, 12, 16, 27, & 39. Wire terminations available with discrete wire and cable.

New MIL-DTL-32689 Standard

Military projects continue to emphasize size, weight, and power (SWaP). SWaP-optimized connector solutions for military and aerospace applications are, therefore, in high demand. The new MIL-DTL-32689 provides multi-sourcing for Mini/Micro-D38999 Series III connectors. (An updated version of MIL-DTL-32689 incorporating Amendment 2 was released January 24, 2023.) Versions from suppliers including Amphenol (M2 Series), Eaton (Souriau micro38999 Series), and ITT Cannon (MKJ Series), are in production with others waiting to see if standardization develops sufficiently to justify their market-entry.

TE Connectivity

TE Connectivity offers micro and nano circular connectors in a range of families for space and weight savings; durability; extreme temperature, vibration, and corrosion resistance; and high-speed data transfer (up to 10 Gb/s).

Design Notes

Like standard versions, micro circular connectors are differentiated by number of pins per terminal (usually three, six, or eight), manufacturing specifications, attachment angles, and modes of connection and disconnection.

Micro circular connectors are available with threaded coupling and push-pull quick disconnect configurations, front panel mount and rear panel mount.

DIN Spec or MIL-Spec

MIL-Spec micro circular connectors are typically waterproof. Micro circular connectors may also provide ingress protection and EMI shielding with well-designed metal shells and gaskets.

Applications: Micro circular connectors are mainly used in mil/aero applications helicopters and jets, military air systems (missiles and rockets), military ground systems (tanks), military communication and computer systems, and marine systems (boats, ships, vessels). They are also used in commercial applications and industrial robotics.

 Glenair Series 806 from Powell Electronics

Glenair Series 806 from Powell Electronics has a reduced thread pitch and re-engineered ratchet to prevent decoupling problems, particularly in small shell sizes, solving one of the major problems of shell size 9 and 11 MIL-DTL-38999 Series III connectors.

Suppliers: Omnetics Connector Corporation, TE Connectivity, Smiths Interconnect, Amphenol Aerospace, ITT Cannon, Avnet, PEI Genesis, Powell, Glenair, Eaton.

Related products:

    • D38999/MIL-DTL-3899
    • Circular connectors

Like this article? Check out our other Meet the Connector, Circular Connectors, and our Mil/Aero Market Page, and our 2022 and 2023 Article Archive

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AJ Born
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