Expanded ultra-high-density reed relay series adds new form factors

Pickering Electronics has expanded its ultra-high-density Series 125, which already offers the industry’s smallest 2 Form A DPST (double-pole, single-throw) reed relay, adding 1 Form A, 1 Form B, 1 Form C, and 1 Form A coaxial options to supply additional switching options. Variants in the expanded range switch up to 1A, 20W and feature 3, 5, or 12V coils, while stacking on a compact 5mm x 5mm pitch. Thanks to instrumentation-grade switches, the relays excel in mixed-signal environments, delivering high insulation resistance and low contact resistance.

“Series 125’s ultra-high-density form factor is designed so that engineers no longer need to compromise between performance and space, making it ideal for those who need to maximise PCB real estate in applications like ATE (automated test equipment) switching matrices or multiplexers,” said Robert King, product manager of Reed Relays at Pickering Electronics. “Already offering the world’s smallest dual-pole reed relay footprint, our expanded Series 125 has now added 1 Form A, 1 Form B, 1 Form C, and 1 Form A coaxial options, enabling record channel density and greater routing flexibility on space-constrained cards.”

Three switch types are now available, the first two featuring sputtered ruthenium contacts for long life and high reliability. Switch type number 1 suits general-purpose applications, rated at 15W/1A (3-5V coils) or 20W/1A (12V coils). It features a layer of copper beneath the ruthenium to help dissipate heat from the contact area, improving current inrush handling and making it more suitable for higher-power applications. Switch type 2 is particularly good for switching low currents and/or voltages, rated at 10W and 0.5A, and should be selected for low-level or cold-switching applications. Switch type 3 is a rhodium changeover switch rated at 2 W, 0.1 A.

The 1 Form A coaxial types are designed for a 50Ω characteristic impedance and are suitable for switching high-frequency RF signals over 1GHz. King added: “Reed relays are the ideal solution for RF signal switching and high-speed digital signal switching, as they offer a smaller footprint and faster response time than EMR, lower insertion loss and better DC load handling than SSR, and superior hot-switching performance compared with MEMS switches.”

Effective magnetic shielding is provided by mu-metal, known for its high permeability and low magnetic remanence. This stops issues caused by magnetic interaction, typically measured as the percentage increase in the voltage required to operate a relay when two further relays, positioned on either side, are also in operation. By comparison, an unshielded device placed next to another would typically exhibit interaction of around 40%. Therefore, without magnetic shielding, even relays of this small size would be unsuitable for applications needing dense packing. Series 125 relays typically achieve interaction of only 1%.

“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, saving significant cost and space,” said King.

An internal diode prevents voltage spikes caused by inductive kickback when the relay coil is de-energised, supplying a path for current to dissipate safely, reducing electrical noise, and protecting sensitive components from damage. 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.