Brian - Read 1.4.12.2 for an explanation of what is meant by a "temperature dependent design."
Per 1.4.12.1, Tma is your product's maximum rated operating ambient, Tamb is the ambient temperature the testing is performed in. If your product is only intended for use in a 25C ambient and the testing is done in a 25C ambient, you're right, the terms cancel out. But, if you product is intended for use in a 40C ambient ad tested in a 25C ambient, the term is nonzero and adjusts Tmax down by the difference of the two ambient temperatures. Regards, Peter L. Tarver, PE Product Safety Manager Sanmina-SCI Homologation Services San Jose, CA peter.tar...@sanmina-sci.com > From: Brian O'Connell > Sent: Monday, June 02, 2003 11:24 AM > > Good People > > Clause 1.4.12.3 of this standard specifies that > "..amount of heating or cooling is not designed > to be dependent on ambient temperature..." does > not seem relevant, because the standard requires > you to find the worst-case test conditions for > evaluation of the component. > > And because of the requirement for worst-case > test conditions, why is the term Tamb - Tma, as > used in the equation to the temperature limit > criteria? As my test conditions must comply by > testing at rated temperature, this term will > always evaluate to zero. So I interpret the > standard so that clause 1.4.12 is the only > criteria required. > > luck, > Brian This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. Visit our web site at: http://www.ewh.ieee.org/soc/emcs/pstc/ To cancel your subscription, send mail to: majord...@ieee.org with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Ron Pickard: emc-p...@hypercom.com Dave Heald: emc_p...@symbol.com For policy questions, send mail to: Richard Nute: ri...@ieee.org Jim Bacher: j.bac...@ieee.org Archive is being moved, we will announce when it is back on-line. All emc-pstc postings are archived and searchable on the web at: http://www.ieeecommunities.org/emc-pstc
