Low-Thermal EMF Reed Relays for Precision Signal Switching

Pickering Electronics has released new comparative test data demonstrating that its compact reed relays significantly reduce thermal electromotive force (EMF) generation in miniaturized low-voltage architectures. The technology targets semiconductor testing, automated test equipment, and precision data acquisition applications where maintaining strict signal integrity is a critical requirement.

Signal Integrity Challenges in Miniaturized Test Systems
As printed circuit boards in automated test systems become more densely populated, engineers face the challenge of mitigating errors introduced by the switching components themselves. In microvolt-level measurement systems, thermal EMF offsets generated across relay contacts act as a meaningful source of error, degrading the accuracy of the acquired data. A switching relay engineered for these applications must preserve the integrity of the measured signal while minimizing the required physical footprint on the printed circuit board.

Thermal EMF Reduction and Operating Principle
The Series 120 relays operate on a 4mm pitch and occupy a board footprint of 3.9 x 3.9 mm, permitting close physical stacking in restricted spaces. According to the newly published testing data, the Series 120 relays produced a final thermal EMF offset magnitude of approximately 46µV. In contrast, a comparable 4mm-class relay produced approximately 403µV, representing an 88.5 percent reduction in unwanted voltage. The devices utilize instrumentation-grade reed switches for stable operation up to billions of cycles. The architecture maintains the inherent characteristics of reed relay switching, including high insulation resistance, low leakage, and low contact resistance, while employing a formerless coil construction and patented SoftCenter technology to improve mechanical robustness.

Robert King, Reed Relays Product Manager at Pickering Electronics, explains the technical necessity of the technology: “As components become smaller and test systems become more densely packed, engineers need to understand the errors that the switching components themselves can introduce. Our testing showed that the Series 120 produced around 8.7 times less thermal EMF offset than the comparable 4mm-class relay we tested. For low-level measurements, reducing that unwanted voltage helps the switching system preserve the signal being measured.”

Additional Context
This section details technical specifications and competitive benchmarking not included in the original product announcement

Within the high-density automated test equipment (ATE) market, switching matrices often rely on ultra-miniature relays from manufacturers like Standex Electronics, Coto Technology, or Teledyne Relays. While solid-state relays (SSRs) are frequently adopted in modern test environments for their infinite lifespan and lack of moving parts, they typically exhibit higher leakage currents and on-resistance compared to electromechanical reed relays. By utilizing instrumentation-grade reed switches with specialized internal construction, the Pickering Series 120 bridges the gap between the ultra-low leakage requirements of high-impedance semiconductor testing and the extreme board density demanded by modern PXI (PCI eXtensions for Instrumentation) matrix modules.

Edited by Maria Brueva, Induportals editor – adapted by AI.

www.pickeringrelay.com