Virendra - I believe that Dupont has some thin, flexible dielectric that can be loaded with ceramic to bump up the dielectric constant. We have found that the best value comes from thin dielectric because it both reduces inductance and increases capacitance resulting in lower impedance. The lower power plane impedance produces more damping, which is a good for reducing power plane resonances. By increasing the dielectric constant alone (no dimensional changes) the capacitance per square area is increased but it turns out that the capacitance available to a power consumer with in a given time frame (i.e. 1 nSec) is the same. This is because the velocity of electromagnetic propagation goes down with increasing dielectric. The cylindrical wavefront that goes out from a disturbance "uncovers" the same amount of capacitance per time, independent of the dielectric constant. So if you are looking for high frequency capacitance to satisfy those fast edges, thin dielectric is good, high dielectric constant is neutral. regards, Larry Smith Sun Microsystems Ray Anderson wrote: > > Typically the way I've seen it done in the past is to use a very thin > dielectric material (~2 mil thick) to achieve the higher than usual > capacitance. > > Most hi-k materials are loaded with some sort of ceramic material which > tends to make them somewhat less than flexible which could be an issue > with a flex board. > > Note that the materials people are always developing new and innovative > solutions, so what was true a couple of years ago when I looked at the > issue may no longer be the case. > > -Ray > > -----Original Message----- > From: si-list-bounce@xxxxxxxxxxxxx [mailto:si-list-bounce@xxxxxxxxxxxxx] > On Behalf Of Virendra > Sent: Tuesday, August 23, 2005 12:11 PM > To: si-list@xxxxxxxxxxxxx > Subject: [SI-LIST] [SI-LIST]: Embedded capacitance on Flex..?? > > Hello All, > Does anyone have experience with embedded capacitance > (wih high K) on a flex circuit board? If yes, are > there any issues with bending the part of the flex > with the high k material..? > > thanks in advance, > > virendra > > __________________________________________________ > Do You Yahoo!? > Tired of spam? Yahoo! Mail has the best spam protection around=20 > http://mail.yahoo.com=20 > ------------------------------------------------------------------ > 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: =20 > //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 > =20 > > ------------------------------------------------------------------ > 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