Connect this: Analyzing connector trends, challenges, and solutions for advancing performance

4Connectors drive many of the key decisions in standards used in open architecture embedded computing platforms as many types of connectors are used in a typical critical embedded system (such as backplane connectors, mezzanine connectors, I/O connectors, and specialty connectors). They also hold the key to realizing advancing system capabilities, and in this regard they have run into problems. This feature discusses the trends, challenges, and future of connectors for critical embedded systems.

At Embedded Tech Trends 2013, Marc Couture, director of product management at Mercury Systems, made this declaration: "We need to speed up without degradation. The connector is the key to unlocking speed!" Marc commented that current advances in connector and backplane technology will get the industry to 8 Gbaud and beyond, but that much more is needed from the connector suppliers for the next-generation fabric interconnects such as PCIe Gen 3, InfiniBand QDR, or 40 Gigabit Ethernet. Marc's thoughts are reflected throughout the industry as system designers struggle to find that perfect connector.

It is impossible to build a computing platform without connectors. Chips, boards, and systems simply need to be connected in some fashion (Figure 1). But, as Marc mentioned, the connector is the key to speed, and unfortunately they have struggled to keep up with the advancements in processor and chipset bandwidth.

Figure 1: Avariety of connectors are on a typical board.
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According to Ken Fleck, Fleck Research, the worldwide production of connectors in 2012 was $40 billion. Bob Hult, Bishop & Associates, has a slightly higher number of $47 billion. Both saw a slight decline in sales from 2011 to 2012 of 4.1 percent and 2.6 percent respectively. Bob is forecasting 2013 to see a 4.2 percent growth to $49.1 billion while Ken is forecasting continued decline of 3.7 percent to $38.7 billion. Ken is basing his predictions on the continued sluggish economies around the world, the new U.S. tax on medical devices, and the cuts in U.S. defense spending that will impact demand in 2013.

Influences across industries

At the 2012 Fleck Connection Conference in December, Ken pointed out several industries and platforms that are creating the most demand and currently have the greatest influence on the connector industry (Table 1). VITA technology suppliers must follow the trends and technologies of these industries and platforms because they are driving the innovation and cost curve of connectors that may possibly have a place in future open architecture specifications. Fortunately, these industries have many of the same problems with connector technologies experienced by critical embedded systems. Consequently, the solutions for these industries can carry over to other industries and apply to critical embedded systems.

Table 1: Industries and platforms influencing connector technology.
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Challenges for connector suppliers

Several challenges are influencing the designs of next generation connectors. In separate presentations at the Fleck Connection Congress in December and Embedded Tech Trends 2013, Fleck Research, Intersil, Bishop & Associates, and TE Connectivity discussed similar challenges to the connector industry (Table 2). All three agree that bandwidth is the single biggest concern for connector suppliers. Followed closely by demand for smaller and lighter connectors for increasingly mobile platforms. All of this while still cognizant of cost sensitivity.

Table 2: Analysts project similar top challenges to the connector.
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Matthew McAlonis, development engineering manager at TE Connectivity, mentioned the connector needs for critical systems from the connector supplier perspective. He listed several needs that his design teams address during the development of connectors. Many of these needs directly address the challenges; for instance, optimizing the weight of connectors has a direct impact on the SWaP requirements faced by system architects (Figure 2). Though the gain may be small, it is very additive with the use of many connectors in a typical platform. A few grams here and there add up very quickly in a large system.

Figure 2: Connector needs for critical systems.

"The most important design concern for connectors in critical embedded computing is always electrical performance Рthis could be signal integrity in a high-data-rate connector or conductivity in a power connector," commented Greg Powers, market development manager at TE Connectivity. "The immediate secondary concern is mechanical performance in the environment, including shock, vibration, temperature, durability, etc. Connectors are truly electro-mechanical systems" (Figure 3).

Figure 3: The Thunderbolt cable is an example of active cable interconnect technology that addresses many challenges of critical system connector needs.
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The future is active

At the Fleck Connection Congress, Intersil's Gourgen Oganessyan, elaborated on active cable interconnects as a way to address many of the challenges. In active cables, small silicon ICs are embedded in each end. The silicon restores signals that have been attenuated over the length of the cable. Active copper-based cables can be used for the lowest cost and lowest power applications while active optical fiber-based cables are ideal for the longest distances. Data centers are already embracing active cables to overcome limitations of existing solutions. The consumer market is more cost sensitive and thus more hesitant to use active cables, but the driving need for ultra-thin product profiles and I/O density are making active cables the only option.

Apple and Intel are promoting Thunderbolt as a revolutionary I/O technology that supports high-resolution displays and high-performance data devices through a single, compact port. It sets new standards for speed, flexibility, and simplicity. Thunderbolt is designed to address the performance and density challenges faced by many computing devices. More and more consumer devices from PCs to peripherals are embracing Thunderbolt technology. There are still cost and power impediments that are slowing adoption, but many of these consumer device designers are left with no other choice. Thunderbolt technology will continue to evolve, making it a better solution. These same issues are facing critical embedded computing platforms, and they are also left with no other choice.

While Thunderbolt is one of the first consumer technologies to go active, others are on the way. PCIe OCuLink, VERA DP 1.2, and HDMI 2 are developing active interconnect options to extend their own roadmaps to the next generation.

Though it has been discussed for many years, optical interconnects are finally showing up in board-level product announcements. Several sections of the VITA 66 VPX fiber optic interconnect specification are complete and suppliers have real products. More work is needed to address the optical backplane, but this is the first wave of what is expected to grow quickly in the near future.

Looking even further into the future, connector suppliers are studying ways to integrate the board connection into the cable to additional reduce the impact that the physical connector has on signals as they pass from the PWB to the connector and on to the transport medium, whether it be copper or optical.