Hello experts,
I would like to ask for your advice regarding our testing fixtures for DIMMs and HDDs in the RMA lab.
The fixtures are located in an EPA, and we are not sure how to perform compliance verification and product qualification measurements to ensure conformity with ANSI/ESD S20.20.
Could you please provide guidance on this?
Thank you very much for your support.
Best regards,
Lucie
Lucie,
ANSI/ESD S20.20 product qualification and compliance verification is for ESD control items. The closest ESD control item that would apply to your fixture is a worksurface.
Product qualification follows ANSI/ESD STM4.1 for worksurfaces. This STM shows how to do product qualification for mats, racks and mobile equipment so you may need to get creative on how you will make the measurements on your fixtures. You want to make sure that points on your fixture that may come in contact with your ESDS items are less than 10^9 ohms to points you intend to use for grounding the fixture. You may want to test many different areas to have the confidence that your fixture is providing the ESD protection you need.
As for compliance verification, you would only need to test one point on the fixture to ground per ESD TR53
The fixture would also need to meet the sections on insulators and isolated conductors from ANSI/ESD S20.20.
Hello, Greetings from India ,
As Andy Sir has cleared already , the nearest compliance test you need to perform is per ANSI ESD STM4.1 as applicable to work surface as the fixture is again your work surface here.
Here you are keeping the fixture on a work surface . Thus ensure that the compliance of that work surface too to meet per STM 4.1
As Andy Sir has confirmed , both for the base work surface as well for the fixture, the Point to ground resistance test per STM 4.1 w.r.t to ANSI ESD S20 20 is to be met .
Thank you.
I think I might take a slightly different approch to this. If I am looking at the picture correctly, the DIMM or HDD are plugged into the various connectors for testing. If this is the case, then the worksurface may not matter unless the parts are placed on the worksurface before they are plugged.
For the fixture, I would ensure that the metal plate is grounded. Once that is done, what is underneath does not matter much. I would measure the fields at the connectors or the plastic that surrounds the connectors to ensure they do not pose a theath. This can be done with a field meter. If they do pose a threat, then use a topical or ionization to minimize the threat. For complinace verification, I would measure the plate to ground and the plastic enclosure.
One additional measurement that should be considered would be to see if the connector pins have any residual voltage on them before inserting the DIMM or HDD. This can be done with a contact voltmeter if you have one. This would be a qualification test not for compliance verification.
Oh, thank you John. There is very nice approach to test fixtures. I mean the voltages onto pins/contacts before switching on the test process by usage of contact voltmeter. There is the best protection against CDM and/or EOS. That opened my mind 
