Industry’s Smallest Two Pole Reed Relay Maximises PCB Real Estate for ATE Designs

­Leading manufacturer of high performance reed relays, Pickering Electronics has introduced its latest high-density reed relay, Series 125 – the industry’s smallest two pole DPST (double-pole, single-throw) reed relay – switching up to an impressive 1 Amp, 20 Watts, while stacking on a compact 5mm x 5mm pitch. This high packing density maximises PCB real estate, making the relays ideal for very high-density applications such as ATE (automated test equipment) switching matrices or multiplexers. The relay also excels in mixed-signal environments, offering high insulation resistance (>1012 Ω) and low contact resistance, thanks to its sputtered ruthenium instrumentation-grade switches.

With 2 Form A (DPST) normally open (NO) contacts, Series 125 relays can switch up to 1 A, 20 W and feature 3, 5 or 12 V coils. Two switch types are available, both with sputtered ruthenium contacts for long life and high reliability. Switch type number 1 is better suited for general purpose applications, rated at 15 W, 1A (3 and 5 V versions) or 20 W, 1A (12 V version). It has a layer of copper beneath the ruthenium to help dissipate the heat from the contact area. This improves current inrush handling ability, making it more suitable where higher power levels are involved. Switch type 2 is particularly good for switching low currents and/or voltages (rated at 10 W, 0.5 A) and should be selected for low level or cold switching applications. 

“With Series 125, engineers no longer need to compromise between performance and space – so it’s ideal for those who need to maximise PCB real estate,” noted Rob King, Reed Relay Product Manager at Pickering Electronics. “Its 2 Form A contacts make it an ideal fit for applications like ATE switching matrices or multiplexers. Full mu-metal magnetic screening enables side-by-side packing without risk of magnetic interaction, allowing a total of 288 Series 125 relays to be placed on a PXI BRIC matrix daughter card to facilitate very high-density switching applications.”

Mu-metal, known for its high permeability and low magnetic remanence, provides effective magnetic shielding. This eliminates issues that would otherwise be caused by magnetic interaction, typically measured as the percentage increase in the voltage needed to operate a relay when two additional relays, positioned on either side, are also in operation. By comparison, an unshielded device placed next to another would typically exhibit an interaction figure of around 40%. Therefore, without magnetic shielding, even relays of this small size would be unsuitable for applications requiring dense packing. Series 125 relays typically achieve an interaction figure of only 1%.

Although small in size, the Series 125 package allows the fitting of an optional internal diode. This prevents voltage spikes caused by the inductive kickback when the relay coil is de-energized. The diode provides a path for the current to dissipate safely, protecting sensitive components from damage and reducing electrical noise. If not fitted, Back EMF diodes may have to be provided externally.

Additional build options are available on request, including unique pin configurations, non-standard coil voltages/resistances, operate/de-operate times, pulse capability, special life testing under specific customer load conditions, and more. 

All Pickering reed relays are highly reliable due to superior manufacturing, testing and quality control processes. They feature instrumentation-grade sputtered ruthenium contacts, rather than the more common electroplated rhodium associated with low grade reed relays with less stable contact resistance. Pickering SoftCenter™ technology minimises internal stresses on the switch, resulting in extended operational life and contact resistance stability. Formerless coil construction enables smaller packages than is typical for this type of device and maximises magnetic efficiency, allowing the use of less sensitive reed switches for optimal switching action and extended lifetimes at operational extremes. Mu-metal screening eliminates problems that would otherwise be experienced due to magnetic interaction when relays are closely stacked. 

Pickering also guarantees reliability through 100% testing of all operating parameters, including dynamic contact wave-shape analysis with thorough data scrutiny to ensure consistency. Unlike other manufacturers that perform only simple DC testing or batch testing, which can lead to non-operational devices being supplied, Pickering performs 100% inspection at every stage of manufacturing. Additionally, Pickering conducts 100% thermal cycling stress testing of the manufacturing processes, ranging from -20°C to +85°C and back to -20°C, repeated three times. This rigorous testing is rarely performed by other manufacturers, often resulting in repeated field failures. Finally, Pickering is committed to product longevity, manufacturing and supporting its reed relays for more than 25 years from introduction, typically much longer.

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