Historically, spring probes have been used for test sockets and compliant interconnects. So have elastomers. But, they usually don’t get teamed-up. When they do, in the form of the patent-pending Hybrid PariProbe®, the results are quite unique.
Why, How, and How Much
The contacts are very short, with low self inductance and low contact resistance.
Compliance is about 25% of the overall contact length.
Made possible by the right materials, and low contact resistance.
< 2mm overall.
|PariProbe®||Hybrid Concept||Machined Stretch Frame|
A simple PariProbe® is a solid metal probe that is positioned between the PariPoser® material and the DUT (Device Under Test) to accommodate unusual shapes of a DUT. (for example: the round shape of BGA solder balls) A Hybrid PariProbe® adds a compression spring to the probe, to increase the compliance per contact.
The Hybrid PariProbe® assembly starts with a sheet of PariPoser® anisotropic elastomer material in a stretch frame. The frame and the material become the base of the socket or the connector, and retain the short spring probes in the one-piece socket body. When the top plunger is compressed, current is passed through the spring probe, then through the elastomer, and on to the PCB.
|Molded Stretch Frame||Cross Section of Probe||One-piece socket body|
Here’s how it works:
|Stretch Frame||The PariPoser® material is pulled taut and glued to the frame to make it easy to handle and attach to the socket body.|
|Socket Body||The one-piece socket body is typically custom machined to retain the spring probe, and to mechanically interface the DUT.|
|External Spring||The large amount of compliance per contact position comes from the compression spring. Putting the compression spring on the OD of the probe’s barrel creates a signal path through the central core of the probe – and then directly through the elastomer. That keeps the CRES (Contact Resistance) low.|
|Bottom Plunger||The bottom of the probe barrel pushes directly on the PariPoser® elastomer, so no bottom plunger is needed. That saves costs, shortens the overall contact length, and prevents mechanical wear on the PCB (Printed Circuit Board) pad.|
|Top Plunger||The top plunger tip can take any shape or coating that is required for the DUT.|
|Sealed Bottom||The sheet of PariPoser® elastomer along the entire surface of the socket bottom seals the socket from the PCB and prevents contamination.|