The changing world of connectors

The once humble plug and socket has now been promoted to the rank of interconnect and with it come all the responsibilities that rank involves.

To meet the changing industry requirements, today’s connectors are expected to be smaller, capable of carrying faster signals at an even greater bandwidth, be very reliable, offer next to nothing in the way of contact resistance and in addition have a quick-release system that eliminates the need for special tools and above all be highly cost competitive.

As a result, the industry is adapting and adopting new strategies for dealing with the advance in miniaturisation that has swept into all areas of electronic equipment - from oil exploration rigs and robotics to washing machines and home theatres to applications in medicine, space and defence.

Industry representatives talk about computing, consumer devices and communications as being the growth driving force behind the next generation of connectors. However, progress is already being made.

Compressing a lot into a small space is a key aim of the electronics industry and ruggedised micro-D connectors are fulfilling part of this aim that often also requires higher operating temperatures and a greater current carrying capacity.

This is evident in the D subminiature connectors that need a pin spacing of 2.54 mm and do not fit in current systems. These connectors are being replaced with a micro-size 1.27 mm device and nanoconnectors at 0.635 mm that are better able to handle today’s technology.

In some applications, currents and voltages are now in the microvolt and milliamp range but the working speed of the connector has increased. As the electronics get smaller, so the space for routing signals becomes more limited and the weight of the interconnect has to be kept to a minimum.

Analog signals, although thought of as yesterday’s technology, are still very much with us but they often require high voltages and thicker wire. This can become a challenge to the connector maker, who must be capable of producing products for both analog and digital use.

The latching micro-D system has emerged as versatile in that it is already a proved design and can be adapted for board and panel mount and wiring configurations and pin counts. It may include metal back shells as EMI protection and strain relief to reduce wear on the cable interface. These connectors are suitable for a wide range of cable types, including open wiring, jacketed cable sets and EMI shielded braid to prevent signal noise or signal intrusion into adjoining circuits.

A simple squeeze and pull disconnects the device and an adapter can be used with existing micro-D connectors, allowing current instruments to use the latch on cable already in a system. With contact counts from nine to 51, the connector shells are made of an aluminium alloy with nickel plating. A one-piece beryllium copper flex pin and a plating of nickel and gold gives the robustness that allows operating temperatures between -55 and 125°C and a special version that is rated at 200°C. While bandwidth may be close to the top of the list for connectors, a close second is the demand for smaller and lighter devices for the growing numbers of mobile equipment.

Specialised connectors such as active cable interconnects are coming into increasing use. Small ICs are embedded at each end of the cable to restore signal strength that might have become attenuated over the cable length. The additional cost of these devices is making the consumer market hesitant to adopt them but the market may eventually have to use them as size and signal density become all-important.

Another direction in which interconnects are moving is with optical fibres that can handle much higher bandwidths. The technology is also seen as a method of linking computers with mobile devices and within computers. One computer manufacturer has evolved a prototype interconnect that uses wavelength division multiplexing (WDM). This multiplexes several signals onto a single optical fibre using different wavelengths (colours) of laser light.

The technique allows bidirectional communication over a single fibre strand and much greater capacity. This could produce the first computer capable of performing a billion computations.

Beyond the conventional interconnects, manufacturers are looking at ways to integrate the board connection into the cable and lessen the influence  the connector has on signals as they move from the printed wiring board (PWB) to the connector and then on to the copper or optical cable.

Thunderbolt is a technology gathering momentum because it supports high-resolution displays and fast data transmission via a single port. Again, cost and power issues are holding back its universal adoption. Thunderbolt is not alone. There are other technologies in the wings such as VERA DP 1.2, HDMI 2 and PCle OCuLink that are poised to take centre stage. Even with a mix of new and old technology, manufacturers, especially in Europe, see a bright future for their industry, according to a report by US company Bishop & Associates. The company’s survey says billings up to May this year were 10.7% higher and bookings increased by nearly 9%. The automotive industry showed strongest growth with industrial while telecommunications equipment showed a slight fall.

Elsewhere in the world, the Asia/Pacific region, including Australia, is showing good growth, which augers well for the new technologies coming online