Electronics Automation

A new series of small-outline-transistor-packaged precision thin-film resistive devices allows circuit designers to place a miniature three-resistor precision network virtually anywhere on a PCB.

A new series of small-outline-transistor-packaged precision thin-film resistive devices allows circuit design engineers to place a miniature three-resistor precision network virtually anywhere on a PCB. The SOT143 Series feature absolute tolerances as low as 0.1% and ratio tolerances between the three resistive elements as low as 0.05%. John Graham, Director of Marketing and Sales at Welwyn, said: "The SOT143 is a standard semiconductor package familiar to most circuit designers and it is ideal for housing our thin film resistive element, providing a low TCR precision resistor capable of handling 0.25W".

The SOT143 Series resistors are finding applications in precision dividers, battery-charging and feedback circuits in computers, instrumentation, power supplies and motor controls wherever precision networks are used.

Rated for a full 0.25W at 70C and 100V, the SOT143 Series resistor networks feature resistance values from 10ohm to 200kohm, in absolute tolerances to 0.1% (ratio tolerances to 0.05%); and with absolute TCRs (temperature coefficient of resistance) of 25ppm/C (TCR tracking to 5ppm/C).

Operating temperature range is from -55 to +125C.

The SOT143 Series resistors are available in three standard sizes (two series networks of three resistors, one isolated two-resistor network).

Each network consists of two or three thin film precision resistive elements, which can be matched in several ratios.

HVC Series thick-film surface-mount resistors exhibit superior power and voltage handling capabilities, making them ideal for use in defibrillators, power supplies and other high-voltage applications.

With the trend towards portable and home use medical devices, the designer faces increased pressure to reduce overall appliance costs, while improving on unit performance and reliability. With these demands in mind, TT Electronics Welwyn Components has refined a thick-film chip resistor family to handle continuous voltages up to 3kV. Designated the HVC Series, the thick-film surface-mount resistors exhibit superior power and voltage handling capabilities, making them ideal for use in defibrillators, power supplies and other high voltage applications.

"Design engineers have traditionally used bulky wire-wound and axial film resistors to achieve the required power and functionality, however these are no longer viable options for medical devices.

The HVC offers a small footprint solution for lower cost manufacture and enhanced unit performance", said John Graham, Marketing and Sales Director of Welwyn Components.

The company achieved the higher voltage ratings through a combination of proprietary materials, special resistor element geometry and adjustment techniques.

Because of their robust thick-film construction and wrap-around terminations to prevent leaching, the HVC Series resistors can be immersed in 260C solder for 30s, enabling the resistors to be mounted on one side of a PC board while leaded components are attached to the other side.

The resistors are fully compatible with high-speed placement equipment and all soldering processes.

With the new extended range, the HVC Series resistors are now offered with limiting element voltages of 1000, 2000 and 3000V in 1206, 2010 and 2512 industry standard chip sizes, respectively.

Power ratings for the three chip sizes range from 0.3 to 1W at 70C.

Resistance values range from 100kohm to 1Gohm, with tolerances down to 0.5% and TCRs to 100ppm/C.

A new series of shielded drum core surface mount power inductors stands just 1.8mm high and claims the highest energy storage density (typically 200nJ/mm3) of any SMT inductors in their class.

A new series of shielded drum core surface mount power inductors stands just 1.8mm high and claims the highest energy storage density (typically 200nJ/mm3) of any SMT inductors in their class. The PG0085/PG0086 series is ideal for local DC/DC conversion. The new series offers high inductance values, up to 3.5uH, a reduced footprint (4.1 x 4.1mm maximum), low direct current resistance and a current rating up to 1.5A.

With its compact, low-cost design, the inductors can be used for a variety of portable electronics devices such as notebooks, PDAs, mobile phones and digital cameras.

ThePG0085/PG0086 shielded drum core inductors offer a self-resonating frequency of more than 40MHz for better filtering effect and performance.

The expanded operating temperature ranges from -40 to +130C, making the inductors suitable for elevated system ambient temperature.

This series is capable of saturation currents of 1.5A DC and heating currents of 3.0A DC, enabling higher current performance in portable applications.

The PG0085/PG0086 series features 25 standard models offering inductances ranging from 0.07 to 3500uH.

Epcos has scored another success in miniaturising ceramic CDMA duplexers.

Epcos has scored another success in miniaturising ceramic CDMA duplexers. Insertion height in particular has been significantly reduced, so that dimensions are now only 19 x 6.5 x 2.7mm for the B59959N1927A360 and 14 x 6.5 x 2.2mm for the D3014. In comparison with duplexers currently in use, component size (volume) has been reduced by about 65% without compromising electrical performance.

The tried and tested properties of microwave ceramic filters include a very low temperature coefficient, extended temperature range (-40 to +85C) and high power compatibility.

In view of their rugged design, some microwave ceramic duplexers are also being tested to automotive specifications.

Premier Farnell was presented with the Fastest Growing Pan European Distributor Award for 2006 at the recent Amphenol Info Com Pan European distribution conference.

Premier Farnell was presented with the Fastest Growing Pan European Distributor Award for 2006 at the recent Amphenol Info Com Pan European distribution conference in Barcelona. Amphenol, one of the largest manufacturers of interconnect products in the world, is broadening its product offering through Farnell InOne in Europe by adding over 450 new lines to both the new catalogue and the web. By the time the new Spring 2007 Farnell InOne catalogue is launched, customers will be able to benefit from over 650 new products, across a whole host of new products ranging from industrial multipole to signal and data.

Ron Vane, Director Europe of Amphenol Infocom, comments: 'Farnell InOne's superb logistics service enables us to give design engineers quick and easy access to the latest technology in high speed data connectors and a full range of multipin commodity products'.

'Through their wide area coverage across Europe, and Asia Pacific, we are gaining a lot of new interesting opportunities'.

Nick Jones, Director of Marketing and Product Development at Amphenol comments: 'To better develop the increasingly broad and diverse product spread, Amphenol has created more support and focus by restructuring'.

'Each of the organisations now offer enhanced local support in all countries and this has resulted in an acceleration of new product additions to the Farnell InOne catalogue'.

Sam Pease, Supplier Account Manager at Farnell InOne adds: 'We have built a very strong relationship with all Amphenol business units at an operational and corporate level, putting in place an extensive 18-month new product introduction plan, which we are confident will be of great benefit to customers'.

'We are delighted to accept the award for Fastest Growing Pan European Distributor as a clear signal of our intention to truly deliver value for Amphenol'.

Moor Instruments needed to find a readily available off-the-shelf transformer that met global medical standards.

Increasingly, aesthetics are being considered alongside effective performance and ergonomics when engineering products/equipment are being introduced to the market, according to Moor Instruments of Axminster. Moor Instruments specialises in the design, manufacture and distribution of laser Doppler systems used for the measurement of blood flow in the microvasculature. Typically these are trolley mounted and principally comprise an arm-mounted imaging system and either an industrial PC or laptop computer.

Power for the equipment is delivered via an isolation transformer that must comply with European medical devices Directive EN60601 Parts 1-1-2 and 1-1/A2 which cover electromagnetic compatibility and general safety, respectively.

Also, because Moor sells worldwide, the transformer must conform to UL2601 Medical Equipment Part 1 and CSA 22.2 No601.1 Medical Equipment, Part 1 UL File E304665, for the North and South American markets.

The company has recently introduced two new models, the moorDLS and moorFLPI to offer its customers, principally in medical research but increasingly for clinical areas, that are more compact and easier to manoeuvre in confined spaces.

These new units are based on a commercially available trolley that is more compact, easier to manoeuvre and visually more pleasing than the previous custom-built ones built for the company.

To facilitate this change, the company needed to find an equally available off-the-shelf transformer that meets the required medical standards.

The solution was the Reomed from REO UK.

This totally self-contained, fully enclosed unit provided a number of bonuses for Moor.

According to Martin Potter, Development Engineer at Moor Instruments: 'It's compact, so it fits neatly into the base of the trolley'.

'It requires no special wiring - unlike the previous transformer, which in turn ensures product consistency/reliability'.

'It is also available in different voltages in the same size enclosure, so no modifications are needed to the trolley for different overseas markets'.

He also added that it would not look out of place on a desk for desktop applications and that the Reomed has a number of IEC socket outlets, enough for both standard applications with scope for adding customer-specific peripherals (external hard disks, printers etc).

Isolating transformers help reduce electric shock hazards and limit the risk to sensitive monitoring equipment of interference generated on the mains distribution network.

REO's Reomed transformers are based on toroidal-core construction, and offer many benefits including low-leakage current, high dielectric strength, low electromagnetic stray fields and a very low value of primary-to-secondary capacitance.

Reomed transformers also provide an additional benefit in that they protect essential electrical equipment connected to their secondary side against an earth single-fault condition by ensuring that power is maintained to the essential equipment.

By using isolation tape and a screen winding between the primary and secondary windings the required dielectric strength of at least 4kV for reinforced and double insulation is achieved, plus the required general earth leakage current of less than 500uA is also achieved.

The compactness of the Reomed results from the cores of the transformers being constructed from electrical-grade steel strip, with a screen winding and tape isolation between the primary and secondary windings.

The core is virtually air-gap free and has very low losses.

Further external protection and mechanical durability is achieved by encapsulation within a plastic housing.

The whole transformer - fuses, input/output sockets and mains switch - is housed within a metal enclosure designed for bench top mounting.

At the moment, REO's MDD compliant range covers standard units for 230 or 115V with power ratings of 300, 600 and 1000VA.

REO also manufactures medical transformers for three-phase 400V supplies rated for up to 8000VA and has designed special versions for building into specialist medical equipment.

A recent report by the Institute for Manufacturing, which claims manufacturing is already gone or going from the UK is flawed, according to Robert Rospedzihowski of Premier Farnell.

A recent report by the Institute for Manufacturing (IFM), which claims manufacturing is already gone or going from the UK is flawed, according to Robert Rospedzihowski, the Global Accounts Director at Premier Farnell. Says Rospedzihowski: "Most UK-based business managers I speak to would strongly disagree with the findings of the report". "In response to cost pressures and dramatic shifts in demand, the volume production of original equipment manufacturing (OEM) has indeed moved to global contract manufacturers which, in turn, have moved out from Western to Eastern Europe and on into Asia".

"However, the low volume OEMs have remained in the West and the UK has a significant advantage servicing them as a result of its impressive skill base of design engineers with sophisticated high-end and niche expertise".

"Low volume OEM customers have many of the same pressures as the high volume players - to increase efficiencies and to reduce overheads for example".

"However, they must also contend with more complicated support service requirements given the small scale research and development aspect of much of their work".

"Catering for such a potentially broad range of services may understandably sound offputting but, by being flexible and working closely with customers to deliver solutions that support their strategy and business, there is a significant new opportunity for the UK manufacturing sector".

Rospedzihowski continues: "Competitive advantage in Premier Farnell's business is increasingly moving from the traditional, and still important, control of the physical flow of goods, to the management and understanding of information associated with that flow".

"Over the last few years we have noticed a distinct trend among customers looking for support in managing and streamlining their procurement processes".

"The long awaited upturn no longer seems such a distant hope and, by continuing to work closely with our customers, supporting them as they require, I have every belief that UK manufacturing will thrive again".

The NTR series is a new family of chip resistors with a high-precision thin-film construction.

The NTR series is a new family of chip resistors with a high-precision thin-film construction. The lead-free devices are ultrastable (10 to 50ppm) across a wide operating temperature range of -55 to +125C. The specification of the NTR series makes them ideal for use in high-frequency applications found in the growing telecommunications and digital equipment markets.

They are also well suited to applications in automotive, test and instrumentation, plus medical and audio.

The low noise and distortion devices have a nickel chromium (NiCr) sputtered, thin-film resistive element on alumina substrate construction.

The wrap-around terminations with nickel barrier and tin finish are compatible with established tin-lead processes, and also with lead-free processes that will be mandatory when new legislation comes into force in July 2006.

The NTR series is available in case sizes from 0402 to 2512.

Resistance values range from 1ohm to 1Mohm, and working voltages from 25 to 150V.