Dear steve When you put all the decoupling capacitor into one corner of the board or distribute them, the impedance of PDS is not same. If I only consider power integrity, is impedance of PDS enough? Best Regards Zhangkun 2004.7.9 ----- Original Message ----- From: "steve weir" <weirsp@xxxxxxxxxx> To: <zhang_kun@xxxxxxxxxx>; <si-list@xxxxxxxxxxxxx> Sent: Friday, July 09, 2004 8:33 AM Subject: [SI-LIST] Re: Is Impedance Enough for Describing the PDS? > Zhangkun, the problem is that the PDS overlaps both signal integrity and > EMC compliance. If the system rules are done right, then the PDS > decoupling problem will eventually reduce to an impedance profile. But > that profile is both spatial and frequency dependent. If I shove all the > decoupling capacitors into one corner of the board I get a very different > result than if I distribute them. > > Steve. > At 08:04 AM 7/9/2004 +0800, zhangkun 29902 wrote: > >Dear all > > > >When talking about power delivery system with other engineer, there are a > >lot of element to describe the PDS, such as energy storage, decoupling, > >bypassing, and so on. I think all these parameter could be described by > >one element, impedance of PDS. > > > >Is my point right? Is impedance enough for describing the PDS? > > > >Best Regards > > > >Zhangkun > >2004.7.9 > > > >------------------------------------------------------------------ > >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 FAQ wiki page is located at: > > http://si-list.org/wiki/wiki.pl?Si-List_FAQ > > > >List technical documents are available at: > > http://www.si-list.org > > > >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 FAQ wiki page is located at: > http://si-list.org/wiki/wiki.pl?Si-List_FAQ > > List technical documents are available at: > http://www.si-list.org > > 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 FAQ wiki page is located at: http://si-list.org/wiki/wiki.pl?Si-List_FAQ List technical documents are available at: http://www.si-list.org 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