I wouldnt agree with the statement that exceeding target impedance at low frequencies is OK. As it was pointed out, this might be acceptable in the ambiguous scenario when we consider the bypass capacitor network only, without the active power source. This scenario is ambiguous because we really need to set the impedance target for the entire network, active source, bypass capacitors and PCB structure. Not doing it this way often leads to the wrong design approach when the antiresonance between the active source and bypass capacitors is missed. There are situations though, when you can convince yourself that it is acceptable to have a higher target impedance at low frequencies. For instance, when the rail powers only SerDes devices with a required minimum transition density. Regards, Istvan Novak SUN Microsystems icer world wrote: > It's said that PDS impedance exceeds target impedeance in low frequency > less than 1kHz is OK , can anyone give me some explains?Thanks! > > > ____________________________________________________________________________________ > Never miss a thing. Make Yahoo your home page. > http://www.yahoo.com/r/hs > > ------------------------------------------------------------------ > 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 technical documents are available at: > http://www.si-list.net > > 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 technical documents are available at: http://www.si-list.net 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