Tuppence from my corner... Once upon at time at Wang Labs, we noticed
emissions performance improved after transportation vibe tests. I attributed
this to having scraped surface oxidation off mating surfaces of shielding
chassis'. A reasonable inference could be made that over time oxides might
build and degrade shielding. this could (and IMO should) inform those with
input to mechanical design.
Cortland Richmond
KA5S
----- Original Message -----
From: Derek Walton <mailto:[email protected]>
To: Mark Schmidt <mailto:[email protected]>
Cc: [email protected];
[email protected]
Sent: 6/15/2010 4:55:22 PM
Subject: Re: [PSES] EMC Performance Changing With Age Of Product
Hi All,
just throwing in my 10 cents from when I worked for an automotive
component
manufacturer. Contary to what a so called expert has written recently, we were
required to test the stuffing out of out parts. Specifically:
We tested 5 parts from a sampled lot of 60. Before we began the EMI
testing,
our 5 parts were sent through some of the environmental tests to simulate
product lifetime. The goal was to age the parts....
The very first test we did was ESD, to wicked levels including the
pins. This
was to simulate being installed in dry climates with no protective measures.
The after sales market was seen as the most severe requirements. Some of the
ceramic caps we initially used showed ESD induced cracks and electromigration.
Our tests included 200 /m testing up to 18 GHz.
While this may not be truly representative of lifetime testing, it was
recognizing that it was important.
Cheers,
Dere! k Walton
L F Research
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