In most PCB PDNs with 5mil or thinner dielectric, 800MHz is getting to be about beyond the point that the cavity dominates over the bypass capacitors with most decoupling schemes. You need to include analysis of your interconnect. Steve Aravind Sandeep wrote: > Hi Subramanian, > At high frequency the conventional decoupling capacitor looks like Besides > the pure capacitance there is an Equivalent Series Inductance ESL and an > Equivalent Series Resistance ESR.Capacitor shows capacitive behaviour in the > lower frequency range; for frequencies higher than the series resonant > frequency the behaviour becomes inductive. Optimum decoupling effect is > found at series resonant frequency. This information should be available in > capacitor data sheets. Although this information is given in the capacitor > data sheet i would recommend to use a simulations before you proceed for > prototyping. > > Thanks and Regards, > Aravind > > > > On 5/22/08, Subramanian R <subramanian1683@xxxxxxxxx> wrote: > >> Hi All, >> We are planning to use a processor running at 800 MHz. >> I was just reading up on the decoupling methods. >> >> The Processor PCB guidelines recommend using 1uF 0402 pack for high >> frequency decoupling. But at 800 MHz, will not the cap/package inductance >> dominate. >> >> The guideline doesn't say anything about plane decoupling also. >> >> Am I missing something? What are the best approaches for decoupling? >> >> Any suggestions will be very useful. >> >> Thank you in advance, >> >> Regards >> Mani >> >> >> ------------------------------------------------------------------ >> 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 > > > > -- Steve Weir Teraspeed Consulting Group LLC 121 North River Drive Narragansett, RI 02882 California office (866) 675-4630 Business (707) 780-1951 Fax Main office (401) 284-1827 Business (401) 284-1840 Fax Oregon office (503) 430-1065 Business (503) 430-1285 Fax http://www.teraspeed.com This e-mail contains proprietary and confidential intellectual property of Teraspeed Consulting Group LLC ------------------------------------------------------------------------------------------------------ Teraspeed(R) is the registered service mark of Teraspeed Consulting Group LLC ------------------------------------------------------------------ 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