Clacton-on- Sea, UK. Pickering Electronics said it plans to release its Series 120 reed relay at SEMICON West 2017 scheduled for July 11-13 in San Francisco. The Pickering Series 120 is a range of single-pole (1 Form A) reed relays that will each require a board area of only 4 mm x 4 mm, making it the highest packing density reed relay currently available, the company reports.
Two switch types are available, a general-purpose sputtered ruthenium switch rated for up to 20 W, 1 A, and a low-level sputtered ruthenium switch rated at 10 W, 0.5 A.
These are the same reed switches used in many other long-established Pickering Electronics ranges but are orientated vertically within the package, allowing this very high density. The small size of the package does not allow an internal diode. Back EMF suppression diodes are included in many relay drivers but if they are not, and depending on your drive methods, these may have to be provided externally.
The relays feature an internal mu-metal magnetic screen. Mu-metal has the advantage of a high permeability and low magnetic remanence and eliminates problems that would otherwise occur due to magnetic interaction. Relays of this small size without magnetic screening would be unsuitable for applications where dense packing is required.
The image to the right has a total of 406 Series 120 relays on an example high-density module, illustrating the packing density of these extremely small reed relays.
The device has pins on a 2-mm square pitch. There are suitable connectors available from some manufacturers, both SMD and through hole, that will allow these relays to be stacked in either a row or in a matrix on a 4-mm pitch.