The series is said to be the industry’s smallest two pole DPST (double-pole, single-throw) reed relay - switching up to 1 Amp, 20 Watts, while stacking on a compact 5mm x 5mm pitch.
According to Pickering this high packing density will help to maximise PCB real estate, making the relays suitable for very high-density applications such as ATE (automated test equipment) switching matrices or multiplexers.
The relay also works well 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 helping to eliminate 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.
For example, 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, the series allows the fitting of an optional internal diode which prevents voltage spikes caused by the inductive kickback when the relay coil is de-energised. 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, and special life testing under specific customer load conditions.
