The bifurcation of the passives components market into very low price ‘commodity’ devices and high specification or custom components is sorting the men from the boys in terms of suppliers.  Customers expect to be offered a solution that addresses the design challenge, rather than only an off the peg component, significantly raising the bar in terms of the technical support that is required.

New Markets
New electronic applications, from LCD televisions to LED lighting, all bring new challenges for vendors of passive components.  Existing systems, including medical, telecommunications, mil-aero and general industrial electronics continually face new challenges that require new passive component solutions.  As a result, whilst oversupply in the standard passive component ranges across the board has accelerated the established downward pressure on prices, interest is growing in areas such as magnetic, timing components and circuit protection.  As each design potentially requires a custom, semi-custom or tailored solution, only those with the right technical capability can play in this market – Abacus, for example, has a team of nine FAEs and product specialists working with customers in this domain.

The macro-trend behind a lot of these changes is the transition from analogue to digital, which is still continuing, often driven by the availability of ever faster DSP and processor devices.  Digital electronic designs brings with them the associated evils of steep pulse edges, overshoot and ringing, which of course are made worse by the ever-present rise in clock frequencies. In power conversion, switched mode power supplies are increasingly used at ever higher switching frequencies.  These design changes are aimed at achieving higher functionality, higher efficiency and/or lower cost but bring in their train a growing level of EMI, as well as sometimes increased susceptibility to interference.  In consequence, EMC legislation is getting stricter, in Europe (EN), the USA (FCC) and Japan (VCCI).  In July 2007 for example, a new mandatory European directive 2004/108/EC came into effect and applies to all equipment brought to market after that date, though there is a two year period of grace for systems already on the market.

Whilst the high volume consumer and business electronics that represents the bulk of the electronic systems in use in the UK today is generally manufactured in the Far East, the same trends can be seen in the medical, industrial, military and telecommunications systems that are the mainstay of our European industry.  Indeed, since many of these applications are to a greater or lesser extent safety critical, designers are giving a great deal of thought to appropriate protection. Identifying a solution is rarely a matter of scanning the available datasheets.  A customer requirement for a transformer will normally be based on a number of windings around a specified core, usually associated with some specific mechanical or electrical constraints.  We are used to seeing full custom transformer designs offered even on relatively low volume applications.  Other inductive products, such as power chokes, can also be tailored to address the challenges of a specific application.

Circuit protection and timing
The same trends are visible in both circuit protection and timing components.  As data rates increase, varistors start to become an economical solution to protect not only the sensitive data or signal lines but also the power rail.  Varistors are often supplied as semi-custom solutions for a particular application, especially in higher power circuits.  This customisation may take the form of a customised mounting technique, taking the component off the board for safety or thermal management reasons.

Increasing circuit speeds are also driving an increasing number of designers to use crystals and other timing components that would have previously been considered specialist.  There are a great number of different factors to consider in specifying these components.  In addition to the basic frequency and precision of the oscillation frequency, designers should look at temperature stability, rise time, jitter, shock resistance, drive circuit requirements and lifetime stability.  An hour or two with an FAE or product specialist who really knows the market can absolutely pay dividends in terms of arriving at a solution that achieves the design objectives at the minimum cost and size.

Thermistors in LED Lighting
New markets bring new opportunities and the new generation of high power LEDs for backlights and the illumination of vehicles and buildings is a case in point.  To achieve the best efficiency, and to maximise the service life of these components, it is essential that the junction temperature of these LEDs is kept below a specified level, and commonly a constant current circuit based on a resistor is used to achieve this.  This is essentially like limiting the speed of a car by driving with the handbrake on – the current is throttled to a pre-set level all the time to prevent the LED overheating.  Of course this approach doesn’t actually prevent the LED getting too hot under a suitable set of adverse conditions – it just reduces the risk.

Active thermal management using a PTC thermistor is much better, allowing higher currents and hence higher levels of brightness to be achieved during ‘normal’ operating conditions, and providing effective protection for the component against damage or failure through over temperature.  As a result, often fewer, lower power LEDs are required, saving cost and space.  This design approach can also eliminate the need for a heat sink. Abacus has a wide range of EPCOS thermistor solutions for LED lighting and are able to recommend suitable devices, based on circuit specifications.

‘Standard’ passives
The volume of ‘standard’ resistors, capacitor and inductor devices used are stable to rising, though prices continue to fall.  To the relief of most of our industrial customers, the trend for case sizes to get ever smaller seems to have flattened off for a while – 0603 continues to be the standard size for industrial electronics and is well and widely supported.  The 0805 case size is also widely available, though the mainly mil-aero customers who seek 1206 sizes are finding themselves paying premium prices to the relatively small number of vendors still supporting this size.

Boxed film capacitors is one area where progress continues to be made in offering the same or higher performance in terms of self healing, higher capacitance, reduced ESR and reduced inductance within smaller case sizes.  Often the best solution for a given design will be a component that is still pre-release with the vendor, so again a relationship with a product specialist who really knows the market well can pay dividends.

It’s the support...
The increasing diversity of passive component solutions on the market, and the growing complexity of some of these solutions, is dramatically changing the picture for vendors and distributors alike.  Many of the more specialist, bespoke solutions are offered by smaller vendors, without the resources to support customers individually.  Distributors like Abacus, that have always taken the issue of design support seriously across the whole portfolio of the components that they offer, are taking the lead in working with customers to implement these solutions in the ever faster digital electronic designs that are being brought to market today.