Mike, > The 3db point > is > Around 10Khz. ... > I also simulated with a Tant. Cap instead of cer cap ... > The draw back is the 3db point now at 100Kz. What were the values of your ceramic and tantalum caps? If must be either a small tantalum cap, or a large ceramic, for the filter's cutoff frequency to have gone UP that much with the tantalum. > If the peak > happens at a non-existing frequency, why do I care? If the peak isn't severe, maybe you don't. However, in many circuits, chances are that sooner or later, something like a data pattern may come along that excites that resonance, and causes problems. In any event, a high-Q peak is just plain trouble. Off-frequency transients would cause it to ring. Regards, Andy ------------------------------------------------------------------ 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