And yet there are any number of boards and systems that have been built using mostly one capacitor value such as 0.1uF that work fine. Steve. Scooby Doo wrote: > Hi Lynne, > > This is what exactly what is wanted to ask. If the slew rate is 1v/ns, then > my 0.1uF capacitor value (designers blindly using value) will not support due > to existance inductive nature at that frequency. > > > So kindly give some reference / notes so that choosing right value. > > > > > --- On Mon, 3/15/10, Lynne D. Green <lgreen22@xxxxxxxxxxxxxx> wrote: > > > From: Lynne D. Green <lgreen22@xxxxxxxxxxxxxx> > Subject: [SI-LIST] Re: PDN related > To: "Scooby Doo" <si.scooby@xxxxxxxxx> > Cc: "SI LIST" <si-list@xxxxxxxxxxxxx> > Date: Monday, March 15, 2010, 5:20 PM > > > Depends on the frequency range where you need PDN clean. > If it is a wide range (generally true) then one would use > more than one value of capacitor. Remember, capacitor > impedance increases at high frequency due to inductive > package effects. > > Lynne > > > "IBIS training when you need it, where you need it." > > Dr. Lynne Green > Green Streak Programs > http://www.greenstreakprograms.com > 425-788-0412 > lgreen22@xxxxxxxxxxxxxx > > > Scooby Doo wrote: > >> Hi SI Experts, >> >> >> I have a question reg PDN. >> >> Suppose an FPGA has 100 I/O pins with 10 VCCO/Gnd pairs. So an average of 10 >> I/O pins for 1 VCCO/Gnd pair. Assume each I/O pin driving 10pf load. >> >> My qn is, to make the clean PDN, is it enough to provide 100pf of capacitor >> to each Vcc/Gnd pair? >> >> I am not convinced with blindly provinding 0.1uF cap to Vcco pins. >> >> kindly clarify. >> >> Thanks in advance for your valuable feedback. >> >> Rajesh >> >> >> > > > ------------------------------------------------------------------ > 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 > > 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 > > Old (prior to June 6, 2001) list archives are viewable at: > http://www.qsl.net/wb6tpu > > > > -- Steve Weir IPBLOX, LLC 150 N. Center St. #211 Reno, NV 89501 www.ipblox.com (775) 299-4236 Business (866) 675-4630 Toll-free (707) 780-1951 Fax ------------------------------------------------------------------ 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 Old (prior to June 6, 2001) list archives are viewable at: http://www.qsl.net/wb6tpu