INTERCONNECTION
Powering Interconnect Reliability: Robust Connections for Mission-Critical Designs
John Brunt, product manager, HRi products at Harwin M
ission-critical applications, ranging from avionics to satellites, military equipment to navigation and industrial systems, must operate consistently for many years. The connector technologies chosen, therefore, must be able to deliver the requisite performance, at the right form factor and weight, while being robust enough to mitigate against potential causes of failure.
This challenge becomes even greater when the target application must operate in harsh environments, sometimes without the possibility of maintenance and repair. A good example here would be space systems, where connector technologies need to meet stringent size and weight criteria and perform to specification, despite rocket and payload launch shock and vibration, as well as exposure to temperature extremes.
Factors to Consider
Outgassing (in space applications) Excessive shock and vibration can lead to pronounced wear of the contacts, so plating thickness and materials are important considerations. High levels of g-force are associated with rapid changes in velocity, such as occurs when a missile is fired, a space vehicle is launched or a racing car comes to an abrupt stop. To ensure the integrity of connections, strain relief where the cable joins the connector may be a pre-requisite.
Extreme temperatures are common to a variety of high-reliability applications and
While each application has its own unique set of challenges, there is a high degree of commonality in factors that designers must consider when selecting/specifying interconnect for mission-critical applications. These can be summarised as: • • • • • •
Vibration and shock Operating temperature Physical knocks Wear resistance Strain relief
Signal and Power Connectors for High-Reliability Designs
A wide variety of connector types are available for hi-rel use to address the varying needs of different applications. Increasingly, these are available with fine-pitch signal contacts, for example 1.25mm, which helps to minimise board area and reduce weight. In recognition of the tough operating environments, many include mechanical features such as threaded Screw-Loks to ensure mating under the most extreme conditions.
Figure 1: Connectors must be correctly specified for high reliability applications
none more so than space applications. As a satellite rotates, in and out of the sun’s rays, for example, the thermal cycling can be as high as 400°C. Additionally, the vacuum of space means that outgassing of plastics used in connectors and other components becomes an important consideration.
It is not only signal connectors that need to address the challenges of high-reliability applications. In modular designs, power also needs to be transmitted from board-to-board or sub-assembly to sub-assembly, making reliable power connectors as equally important as their data counterparts. That is why Harwin developed the M300, a series of rugged and compact power connectors that combine up to 1,000 mating cycles with the ability to operate at a temperature range from just -65°C to as high as 175°C. These connectors are designed on a 3mm pitch, are rated at 10A per contact and offer between three and ten contacts in single- or dual-rows.
For higher power requirements, Harwin’s Kona range of high-reliability, lightweight, 8.50mm-pitch power connectors, which are capable of 60A of continuous current per contact, are designed to maintain electrical continuity under heavy vibration and shock and extremes of temperature. Pin counts of two, three and four deliver maximum combined currents up to 240A and accommodate voltages to 3kV. Six-finger beryllium copper and gold-plated contacts are individually shrouded on both male and female connectors to prevent physical damage, while an innovative
Figure 2: The compact and rugged M300 series is intended for power interconnect in high reliability applications
36 OCTOBER 2024 | ELECTRONICS FOR ENGINEERS
mate-before-lock mechanism prevents any damage during the locking process by ensuring the contacts are fully mated before engaging the fixings.
www.harwin.com
Page 1 |
Page 2 |
Page 3 |
Page 4 |
Page 5 |
Page 6 |
Page 7 |
Page 8 |
Page 9 |
Page 10 |
Page 11 |
Page 12 |
Page 13 |
Page 14 |
Page 15 |
Page 16 |
Page 17 |
Page 18 |
Page 19 |
Page 20 |
Page 21 |
Page 22 |
Page 23 |
Page 24 |
Page 25 |
Page 26 |
Page 27 |
Page 28 |
Page 29 |
Page 30 |
Page 31 |
Page 32 |
Page 33 |
Page 34 |
Page 35 |
Page 36 |
Page 37 |
Page 38 |
Page 39 |
Page 40 |
Page 41 |
Page 42 |
Page 43 |
Page 44 |
Page 45 |
Page 46 |
Page 47 |
Page 48 |
Page 49 |
Page 50 |
Page 51 |
Page 52 |
Page 53 |
Page 54
