Specifying the design rules

01 January 2008

JAE PCB and cable-mounted connectors, from Rutronik
JAE PCB and cable-mounted connectors, from Rutronik

The distribution market is looking a little glum, as component distributors report a mild downturn across Europe. However, others are finding this as a chance to specialise, diversify and explore new markets

Apparently, it was inevitable. After a run of successful quarters, DMASS (Distributors’ and Manufacturers Association of Semiconductor Specialists) reports a decline of 3.8 per cent in semiconductor distribution in Q3 2007. Although last year, as a whole, figures are only 0.6 per cent down on 2006, thanks mainly to a record start to the year.

Ian Bass, chairman DMASS, puts the decline down to the weak dollar, inventory correction over the last few quarters and the ‘massive’ price differences to Asia. Across Europe, Germany remains the biggest market, with only 1.8 per cent decline against Q3 2006 and sales of €434million. It is still way ahead of the second largest market in Europe, Italy, worth €155million, which dropped 3.8 per cent in that quarter. Some regions showed double-digit growth, however. Eastern Europe is one and is closing on Italy with sales of €153million. Benelux is the other growth region, although more of a minnow, valued at €54million. The UK, one of the larger markets saw a dramatic drop, declining 18.5 per cent with sales totalling €127million, followed by France, achieving €107million, a 13.2 per cent drop.

As far as products go, some product areas saw growth in Q3, 2007, namely IGBTs, SRAMs, standard analogue and microcontrollers, while other memory types, microprocessors, programmable logic, opto, DSP and advanced analogue all fell.

Bass remains optimistic about the general state of the mainstream distribution portfolio. He saves his concern for how Europe can ‘shed its image as a mature electronics market and develop dynamics around its core competencies [industrial, automotive and environmental technology].’

Some distributors take the diversification message seriously. Anglia Group has added a lighting division for optoelectronics, including LEDs from Avago Techolgies, including moonstone warm white power 1W, high brightness LEDs. It is one of the thinnest packages in the industry, claims Avago (www.avagotech.com) at just 3.3mm high and has a 110° viewing angle. It is also energy-efficient. The exposed pad transfers heat from the package to the motherboard efficiently, thermal resistance is just 10C/W and drive current is 350mA. It is designed for ultra-high-brightness LED applications such as decorative lighting. Other Moonstone LEDs are available in cool white, blue and green.

Other LEDs from Cree, drive circuitry from Zetex and Power Integrations, microcontrollers from STMicroelectronics and Microchip are also offered by Anglia. Thermal management is covered with heatsinks from Aavid Thermalloy and Calinar and fans from NMB Minebea.Secondary optics, standard or customised lenses for lighting design, from Polymer Optics and aluminium-clad PCBs are available through the distributor’s partnerships.

This new departure into lighting design is partly to attract new customers, admits Steve Rawlins, managing director, Anglia Group, but also as designs can include lighting aspects unfamiliar to electronic design engineers. Lighting is used in most applications, from automotive design to the increase in demand for intelligent signage for safety and information- where would Britain’s motorways be without such signage? Rawlins goes on to correct me, it is not just motorway information, but street lighting, exit lighting for cinemas, even lighting for warships that Anglia has identified as target markets. Putting clusters and drivers in PCBs, with thermal management can be issues for non-technical engineers, he continues, explaining Anglia’s lighting website www.anglia-lighting.com. The site has summaries of product features, a parametric search to identify the most appropriate component and a design guide, with all the steps in a solid state lighting project from defining initial requirements to estimating efficiencies of parts, calculating the number of LEDs required, choosing the optical, thermal and electrical combinations to board layout and prototype testing.

To provide support across all its divisions, Anglia announced its technical design facility last year, Anglia Designs (www.anglia-dsigns.com) complete with a laboratory and hardware/ software design suite, CAD/CAM and an EMC pre-compliance test facility.

Special order
Some distributors specialise in product areas. Trident is one, (www.trident-uk.co.uk) specialises in displays, SBCs and panel PCs and has added this marine- grade display and panel PC from Winmate. The bridge LCD and panel PC are certified to IP65 and have aluminium housing, sealed to IP54 at the rear. The duo accepts multi-video inputs, such as DVI, VGA, S-video or composite video and also supports picture-in-picture.

The touchscreen can be either SAW (surface acoustic wave) touchscreen or a five-wire resistive touchscreen. There is also an anti-reflection, protective glass option. The LCD uses hyper dimming to control backlight brightness linearly for almost zero to 100 per cent, making it able to be used in all brightness conditions. Input voltage ranges form 8V to 36V with AC power input optional for the larger models, i.e. from 12in to 23.1in. LCDs range in size from 8.4in to 23.1in.

The transflective film technology used is useful for maritime applications, where visibility in outdoor or bright ambient environments is called for. Applications cited by the company as practical for the PC and display are radar, navigation, automatic identification, monitoring and surveillance systems.

The panel PC provides fanless, low power computing, using an AMD CS 5536 chipset. It is available with two USB 2.0 ports, three COM ports, VGA and LAN and a compact flash socket. Panel sizes range from 8.4in to 19in, the 12.1in and 15in models are high brightness.

Hi-rel RoHS
One distributor has highlighted a problem that has come about as a result of the RoHS directive which affects military and aerospace industries despite being exempt from the directive. Companies in these sectors, reports Aerco (www. aerco.co.uk) are exempt from the legislation but are still affected by the changes this directive has brought about for their customers.

Many of the popular components that contain a combination of tin/lead plating are now obsolete or in short supply as component manufacturers have reduced production. If they are available, they are on long delivery times according to Aerco.

Aerospace and military vehicles and satellites are exempt because pure tin can grow ‘whiskers’ from the surface which can bridge closely-spaced circuits and short them. Obviously, in mission critical applications, this risk is too big. Hence the exemption. However, a side-effect of the directive is a shortage of components that are suitable for high-reliability applications. Aerco is tackling this by increasing its stock of such components. It is also helping customers source alternatives, such as gold. According to managing director, Rob Laughtom, ‘ We have already helped major customers, such as Ratheon and Astrium and we now supply these….. and other companies with components that are guaranteed to be free of pure tin’.

Connector link
Aerco also stocks Quick-Lock-Standard (QLS) RF connectors from Telegartner. These are a quick connect version of the sub-miniatrue SMA standard connectros. Tney offer low-loss RF performance up to 6GHz and use a patented push-pull locking system that are claimed to reduce engagement time by 90 per cent. The connectors also save space in panel mounting, as a torque spanner is not needed. Contact force is 200N to optimise electrical performance. Impedance is 50Ù and working voltage is less than 500V at 50Hz.

Finally, representing DMASS’s ideal business conditions, German distributor Rutronik (www.rutronik.com) has released details of the JAE PCB and cable-mounted connectors for external PCI Express card and PCIe interconnects.

The DE1 series includes cable-mount plugs, with a mechanical lock to ensure correct mating, and PCB-mount receptacles with through-hole pin termination. Each connector has 15 contacts to interface directly with PCI Express Card interconnects. They also support PCIe transmission. For enhanced signal integrity the connectors have a staggered contact arrangement on a 1.27mm pitch, which is claimed to minimise crosstalk and meet PCI-SIG mechanical and electrical specifications. Contact resistance is low, 30mÙ which allows designers to optimise cable lengths. Current rating per contact is 0.5A so the connectors can be used in external connection of PCIe cards, interconnecting systems and to link evaluation or development boards to a host board or PC.

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