Is there any time limit on how long a test result is valid for an EMC test - if
the product hasn't changed. CB reports have a 3 year shelf life, after which
the various CB participants are obligated to take the reports on face value and
could require inspection or retest, but I don't know if
On 2012-05-29 18:15, McInturff, Gary wrote:
I'm inclined to test, the customer is not.
Chips are likely to be faster now. PC board layout and material may have
changed. I suggest a 'pre-compliance' check to see if a full re-test is
needed.
--
With compliments
-
I've had a number of cases where an IC vendor did a die shrink on an IC without
rescaling the pin drivers. Even though the IC ran at the same speeds, the edges
were much sharper leading to problems at higher harmonics. I would suspect that
a number of ICs in your system have undergone die
Thanks Ted, John Woodgate suggested the same thing, and I hadn't thought about
that aspect. Nice catch
Gary
From: Ted Eckert [mailto:ted.eck...@microsoft.com]
Sent: Tuesday, May 29, 2012 10:39 AM
To: EMC-PSTC@LISTSERV.IEEE.ORG
Subject: Re: [PSES] Statute of limitations
I've had a number of
Where this happens even more frequently is in switching FETin SMPS-es.
Modular plug-in, OEM or self designed, chances are good that the FETS
you buy today are MUCH faster than their equivalent (or even same type)
a few years ago. Expect harmonics to 200 MHz, where an upper limit of 30
MHz was
Common sense and confirmation from following this thread it is clear that as
components 'improve' and change there is great likelihood of upper tones
creeping up, possibly out of compliance on marginal products.
What is NOT clear is whether knowing that is likely MUST a retest be done.
Would
It was pointed out to us that our 50 kHz system was radiating around 5 GHz.
We checked and indeed it was. Glory be to Average measurements!
From: ce-test, qualified testing bv - Gert Gremmen g.grem...@cetest.nl
To: Ted Eckert ted.eck...@microsoft.com;
Hello and thank you for doing this study.
However I would point out that your study does NOT cover real world scenarios
as pwb costs
as so high that to put in 65mil guard traces is problematical.
From: si-list-bou...@freelists.org
Hi Gary,
Ted brought up a good point that for me has proven in a past life for a fairly
benign EMC-passing product to produce a surprising comb generator effect that
created a few headaches to deal with. Also, the EU's harmonized standards lists
are regularly updated to indicate new/revised
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