Jim, You have my sympathies. Some manufacturers don't seem to realize that their so called product "improvements" may actually cause undue grief and hardships on their customers. "Specifications subject to change without notice" is a common catch clause associated with far many products on the market these days.
In one company where I worked many years ago, we had an incoming inspection department that routinely carried out random samplings and measured critical parameters for crystals and semiconductors. With this approach, most out-of-spec devices simply did not make it to the store bins. On the brighter side, speeding up a FET is hard to do. Slowing it down in a circuit is much easier for EMC purposes. --------------------------------------------------------------------- Dan Kwok, P.Eng. Principal Engineer Electromagnetic Compatibility Intetron Consulting, Inc. Ph (604) 432-9874 E-mail [email protected] Internet http://www.intetron.com ----- Original Message ----- From: "Jim Eichner" <[email protected]> To: <[email protected]>; "Jim Eichner" <[email protected]>; "'EMC-PSTC - forum'" <[email protected]> Sent: Wednesday, October 24, 2001 11:54 AM Subject: RE: Shrunk-die power MOSFET's and compliance > > Well for example, I have just finished specifying what compliance re-testing > I am going to need to do on 4 different products whose power conversion > stages use IRF630's, IRF740's, IRF840's, and RFP50N06's, but the list goes > on and on. If you are using power FET's in power electronics, chances are > they have changed or will soon. The main manufacturers that come to mind > are IR, Fairchild/Harris, Philips, and STM-Thomson. Not all have forced > changes to the shrunk-die version - some have agreed to keep the old style > available - and all have at least added a suffix to their markings on the > devices so you can tell if it's the new revision die or old. In one case, > however, we received modified parts with no markings differentiating them > from the old rev parts, for almost a year with no communication from the mfr > telling us about the change. We found out through other channels and then > contacted them. They seem to be behaving as if fundamental changes to the > performance and specifications of the part are none of our business. > > I am re-doing radiated and conducted emissions, some thermal testing, and a > bunch of functional testing and looking at waveforms on 4 different products > affected by this change. Those are only the products I am responsible for - > as a company we're doing functional testing and possibly compliance > re-testing on many more products. > > This is not a simple component substitution exercise, if your products are > or use power electronics! I would advise everyone potentially affected to > have your procurement department look into this. > > Regards, > Jim Eichner, P.Eng. > Manager, Engineering Services > Xantrex Technology Inc. > Mobile Power > web: www.xantrex.com <http://www.xantrex.com> > Any opinions expressed are those of my invisible friend, who really > exists. Honest. > > > ------------------------------------------- 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: [email protected] with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Michael Garretson: [email protected] Dave Heald [email protected] For policy questions, send mail to: Richard Nute: [email protected] Jim Bacher: [email protected] All emc-pstc postings are archived and searchable on the web at: No longer online until our new server is brought online and the old messages are imported into the new server.
