Alex, You can get these and many more answers from the book EMC and the Printed Circuit Board by Mark I. Montrose (ISBN 0-7803-4703-X). I am also giving below the details about EMC-PSTC discussion list, which is a better forum for such questions. Regards, Ravinder Server PCB and Flex Development Hitachi Global Storage Technologies Email: ajmani@xxxxxxxxxx *************************************************************************** Always do right. This will gratify some people and astonish the rest. .... Mark Twain ******************************************************** 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: majordomo@xxxxxxxx with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Ron Pickard: emc-pstc@xxxxxxxxxxxx Dave Heald: daveheald@xxxxxxxxx For policy questions, send mail to: Richard Nute: richn@xxxxxxxx Jim Bacher: j.bacher@xxxxxxxx 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 **************************************************************** "Alex Achey" <alexachey@sesi-m To: <si-list@xxxxxxxxxxxxx> d.com> cc: Sent by: Subject: [SI-LIST] Power supply inductors and EMI beads si-list-bounce@fr eelists.org 05/22/2003 01:50 PM Please respond to alexachey Hello all, I'm a relatively new engineer still wet behind the ears with this EMI and noise stuff. I'm trying to figure out where is and is not an appropriate place to put power choke coils, power filtering, and EMI beads. I have a board I'm putting an FPGA on with some other stuff which generates a moderate amount of digital noise, along with my regulators to get my 12V input down to 5/3.3/1.5V. Should I be putting a choke coil on the power supply + input only or the ground (-) input also? Should I tie my signal ground to chassis ground with my mounting hardware? Are EMI supression beads appropriate for both power and ground inputs from the supply? I apologize if these are really basic or "dumb" questions but I can't seem to figure this out. Thanks, Alex ------------------------------------------------------------------ To unsubscribe from si-list: si-list-request@xxxxxxxxxxxxx with 'unsubscribe' in the Subject field or to administer your membership from a web page, go to: //www.freelists.org/webpage/si-list For help: si-list-request@xxxxxxxxxxxxx with 'help' in the Subject field List archives are viewable at: //www.freelists.org/archives/si-list or at our remote archives: http://groups.yahoo.com/group/si-list/messages Old (prior to June 6, 2001) list archives are viewable at: http://www.qsl.net/wb6tpu ------------------------------------------------------------------ To unsubscribe from si-list: si-list-request@xxxxxxxxxxxxx with 'unsubscribe' in the Subject field or to administer your membership from a web page, go to: //www.freelists.org/webpage/si-list For help: si-list-request@xxxxxxxxxxxxx with 'help' in the Subject field List archives are viewable at: //www.freelists.org/archives/si-list or at our remote archives: http://groups.yahoo.com/group/si-list/messages Old (prior to June 6, 2001) list archives are viewable at: http://www.qsl.net/wb6tpu