Key Considerations for Selecting the Right Connector for Rugged Applications

Connectors are essential components of electrical and electronic systems used in various applications. Subsequently, the reliability and performance of a connector in the desired product are critical. If the connector is not up to par, the system could fail or perform poorly, which may hamper productivity, delay product shipments, create financial loss, and tarnish a company’s reputation. Therefore, the choice of a connector is essential for the end product's success.

Guidance for choosing connectors

The user must consider several key factors before selecting an appropriate connector for an application. Without thorough knowledge and hands-on experience, it is difficult for an inexperienced engineer to foresee the myriad of factors that must be considered. Novice and young system designers may also need help in selecting the optimal connector for a product that must perform reliably in harsh environments.

Applying their decades of experience across a wide range of rugged applications and vast knowledge of producing a wide variety of connectors, Harwin engineers have generated seven factors for system designers to consider before selecting an appropriate connector for their respective application. They include vibration, dimension, design complexity, electromagnetic interference (EMI), data transmission speed, durability, and supply chain reliability. Because of the rapid evolution taking place in harsh sectors like industrial, IoT, and transportation, designing a system requires not only adapting to current needs but also taking into account future requirements.

Considering key factors

In industrial and other heavy machinery applications, systems are exposed to high levels of vibration that can lead to physical damage and loss of signal integrity due to misalignment of pins. Key manufacturers, like Harwin, have designed and developed connectors that can resist vibrations as high as 20 Gs, providing connectors with guaranteed reliability and performance in demanding conditions.

With miniaturization trending, connector size is another important factor. Compact form factors, surface-mount housings, and shrinking pin-pitch are also popular with connector makers. Likewise, with advances in technology, connectors are also accommodating greater tolerance to misalignment.

Similarly, with the rapid proliferation of electronics in modern systems, EMI is an ongoing problem on populated printed circuit boards (PCBs) and circuit enclosures in industrial and other similar rugged environments. Besides addressing the EMI issue on PCBs and enclosures, the user must also ensure that the selected connector can mitigate existing and future EMI levels. A common practice to mitigate EMI in connectors is to encase them in conductive material, which acts as a shield. To create an effective barrier, the conductive shield is also grounded.

Also, in applications where high-density and high-speed interconnects are needed, like in industrial automation and data center backplanes, insertion loss and crosstalk performance may also be considered an important selection criteria.

Durability is another important connector characteristic. Designers must determine the number of mating cycles a connector will undergo in its lifetime. Based on these calculations, the designer must decide if a standard connector is suitable for the task or if a dedicated high-reliability model is needed.

Designers must also ensure that the distributor of connectors is trustworthy and reliable, and that it implements the Electronic Components Industry Association (ECIA) standard to prevent counterfeit components from entering the market. It is also equally important to choose the right connector manufacturer, which will ensure quality and reliability of the product in the toughest conditions while guaranteeing quality supply in the future.

One such dependable quality manufacturer in the market is Harwin, which has developed the Kontrol family of durable, reliable, and vibration- and shock-resistant connectors that support numerous pin counts and form factors for demanding mission-critical applications where failure is not acceptable.

In keeping with changing needs, Harwin continues to expand the Kontrol M55 portfolio with improvements in performance. The newest additions offer a pitch of 1.27 mm as a space-saving option for crowded PCBs (Figure 1). Designed to withstand high vibration levels in industrial and embedded applications, the M55 connectors are fully shrouded and include additional retention tabs to enable them to withstand vibrations as high as 20 G for over 12 hours. They are also designed and tested to withstand high levels of shock, and feature locking mechanisms to maintain a secure connection. Other key features include 500 mating cycles, 3 Gbps data transmission speed, 1.2 A per contact current rating, surface-mount (SM) housings, and a wide operating temperature range of -55°C to +125°C.

Figure 1: Harwin expands the Kontrol series by adding rugged, single row connectors and cable assemblies to the 1.27 mm family. (Image source: Harwin)

To accommodate numerous design layouts, the M55 SM connectors come in both vertical and horizontal PCB mounts, with options to select from a range of pin counts that offer scalability for different signal and power needs.

To provide a board stacking option on a PCB where vertical space is at a premium, the Kontrol series offers the vertical socket M55-6002042R with 20 contacts in a 10 + 10 configuration (Figure 2). This double row SM connector comes with a height of 6.25 mm, and features location pegs and hold-down retaining tabs for additional solder strength.

Figure 2: The Harwin Kontrol M55-6002042R is designed for PC board stacking. (Image source: Harwin)

For board-to-board connections, a sturdy horizontal header with 80 contacts in a 40 + 40 layout is available. Like other members, the M55-7108042R SM board-to-board connector offers robust construction with fine-pitch spacing and industrial durability for harsh environments. 

Another member to join the Kontrol series is the M55-8201242 (Figure 3), a 12-position, double-row female IDC cable connector that uses 30 AWG ribbon cable with 0.635 mm pitch to create off-the-shelf cable assemblies. The connector’s integrated latches secure mating and ensure performance under tough conditions in industrial and other similar harsh applications.

Figure 3: IDC cable connector M55-8201242 uses 30 AWG ribbon cable to create an off-the-shelf cable assembly. (Image source: Harwin)

For added location tolerance, which is needed when multiple connectors are used to connect the same two PCBs, Harwin has introduced their Flecto floating connectors (Figure 4). A board-to-board electromechanical interconnect for data and/or power, they are crafted to provide movement in the X, Y, and Z axes of the male connector. Designed to withstand up to ±0.8 mm misalignment from the centerline, these fine-pitch, high-pin-count board-to-board connectors offer complete alignment, high-speed data transmission, mixed-signal and power options, high contact reliability, and multiple mounting options. Unlike traditional connectors, the floating connectors feature a spring-like mechanism to provide elasticity to take stress off both the solder joints and contact pins.

Figure 4: Flecto floating connectors provide movement for added location tolerance. (Image Source: Harwin)

Conclusion

Besides selecting the right connector for the harsh conditions found in industrial and similar demanding applications, choosing a dependable certified source, like Harwin, is equally important. The two go hand in hand to ensure that the selected component performs reliably in the toughest environments.