Posted for Jack Cook:
------------------------ From: "Cook, Jack" <[email protected]> Subject: RE: RE: Ferrite pads vendors Date: Mon, 5 Apr 1999 10:31:16 -0700 To: 'EMC-PSTC' <[email protected]> Cc: "Cook, Jack" <[email protected]> > As noted by others, Steward makes stick-on ferrite discs. I used one on top > of a surface mount oscillator (50 MHz) and it worked dramatically at one > problem harmonic (can't remember which now). At 25 cents (if memory > serves), it was a cost effective fix, at least until the next board > revision. > > Incidentally, sometimes I use chunks of ferrite on boards simply as a > trouble-shooting technique. > > Jack Cook, > Xerox Corp. > > > -----Original Message----- > From: Upson, Darrel [mailto:[email protected]] > Sent: Monday, April 05, 1999 8:40 AM > To: 'emc-pstc group' > Subject: FW: RE: Ferrite pads vendors > > > 6 years ago in a product that was failing our radiated emissions limits I > tried a ferrite sheet that was placed under the cpu clock oscillator with > holes for the leads to run through. The material was about 2mm thick. > Unfortunately I am unable to find the manufacturers part number at this > time. We never released that part to manufacturing. The clock fundamental > frequency was 20MHz and there was an emission at 225MHz that was over the > limit. The ferrite reduced that emission about 9dB. > > Darrell > -----Original Message----- > From: Knighten, James L [mailto:[email protected]] > Sent: Friday, April 02, 1999 11:00 AM > To: EMC-PSTC > Subject: RE: RE: Ferrite pads vendors > > > To All: > > Regarding these layers of ferrites that can be placed either above, or below > an IC, a few people have indicated that "they work." > > Can anyone be more specific? What does it mean that "they work?" > > Jim > > Dr. Jim Knighten e-mail: [email protected] > <mailto:[email protected]> > Senior Consulting Engineer > NCR > 17095 Via del Campo > San Diego, CA 92127 http://www.ncr.com <http://www.ncr.com> > Tel: 619-485-2537 > Fax: 619-485-3788 -------------------------- Ed Price [email protected] Electromagnetic Compatibility Lab Cubic Defense Systems San Diego, CA. USA 619-505-2780 List-Post: [email protected] Date: 04/05/1999 Time: 11:30:38 Military & Avionics EMC Services Our Specialty Also Environmental / Metrology / Reliability -------------------------- --------- This message is coming from the emc-pstc discussion list. To cancel your subscription, send mail to [email protected] with the single line: "unsubscribe emc-pstc" (without the quotes). For help, send mail to [email protected], [email protected], [email protected], or [email protected] (the list administrators).
