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 RETEST be required as 'due diligence', or maintenance of CB, or instead, as the client desires, simply 'ostrich' it? As with most expenditures for EMC issues, need to point to the legaleze that requires it. Regards, Robert Macy, PE AJM International Electronics [formerly in Silicon Valley] P O Box 74241 46007 N 38th Ave, Suite 100 New River, AZ 85087 tel: 480 466 0895 fax: 623 465 2974 [email protected] --- [email protected] wrote: From: "ce-test, qualified testing bv - Gert Gremmen" <[email protected]> To: [email protected] Subject: Re: [PSES] Statute of limitations Date: Tue, 29 May 2012 20:20:39 +0200 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. Gert Gremmen Van: [email protected] [mailto:[email protected]] Namens Ted Eckert Verzonden: dinsdag 29 mei 2012 19:39 Aan: [email protected] Onderwerp: RE: Statute of limitations 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 shrinks. The IC vendors are always looking for ways to get more chips out of a single wafer. Ted Eckert Compliance Engineer Microsoft Corporation [email protected] The opinions expressed are my own and do not necessarily reflect those of my employer. From: McInturff, Gary [mailto:[email protected]] Sent: Tuesday, May 29, 2012 10:16 AM To: [email protected] Subject: Statute of limitations 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 the same is true for EMC test when meeting the EU directives. Actually I guess the requirement for a CB update every three years isn't truly a requirement for meeting the directives either. The CB report is a tool to help show conformity. Bottom line the last EMC test was in 2004, and the clock speeds are pretty low - 12 MHz, so I don't think even the new upper frequency test range requirements of EN55022 affect the results. I'm inclined to test, the customer is not. Gary McInturff Reliability/Compliance Engineer Esterline Interface Technologies Featuring ADVANCED INPUT, MEMTRON, and LRE MEDICAL products 600 W. Wilbur Avenue Coeur d'Alene, ID 83815-9496 Office:208-635-8306 Cell: 509 868 2279 Toll Free: 800-444-5923 X 1238 [email protected] <mailto:[email protected]> www.esterline.com/interfacetechnologies <http://www.esterline.com/advancedinput> Technology, Innovation, Performance... - ---------------------------------------------------------------- This message is from the IEEE Product Safety Engineering Society emc-pstc discussion list. To post a message to the list, send your e-mail to <[email protected]> All emc-pstc postings are archived and searchable on the web at: http://www.ieee-pses.org/emc-pstc.html Attachments are not permitted but the IEEE PSES Online Communities site at http://product-compliance.oc.ieee.org/ can be used for graphics (in well-used formats), large files, etc. Website: http://www.ieee-pses.org/ Instructions: http://listserv.ieee.org/request/user-guide.html List rules: http://www.ieee-pses.org/listrules.html For help, send mail to the list administrators: Scott Douglas <[email protected]> Mike Cantwell <[email protected]> For policy questions, send mail to: Jim Bacher: <[email protected]> David Heald: <[email protected]>
