I am also under the impression that the surface mount pad and via structure on PCB will be the larger inductance vs. the capacitor itself. Any drop in inductance based on smaller capacitor size will be small compared with the pad and via inductance. Chris -----Original Message----- From: Ray Anderson [mailto:Raymond.Anderson@xxxxxxx] Sent: Thursday, May 16, 2002 2:02 PM To: si-list@xxxxxxxxxxxxx Subject: [SI-LIST] Re: Decoupling capacitors Another thing to consider regarding Y5V parts is the loss of rated capacitance when DC bias is applied. Y5V parts exhibit a loss of about 85% capacitance at a bias level of 6vdc. i.e.: a 100uF part will actually have about 15uF capacitance at 6 vdc bias. X5R (which is similar to X7R) parts exhibit a 40% loss of capacitance at 6vdc. A 100uF part will have 60uF capacitance at 6vdc. Be sure to understand all the curves on the data sheets and ping your selected vendor for more detailed info. -Ray Anderson Sun Microsystems > >Decoupling capacitors 0603/X7R/100nF versus 0402/Y5V/100nF > >Although 0402 pkg. has less inductance (that matters), 100nF caps in that >package are only available with Y5V dielectric and our EE has the following >concerns: > >1. Self-resonant frequency is lower (5MHz for Y5V versus 20MHz for >X7R) > >2. Limited temperature range (+22%-82% capacitance for Y5V versus >+/-15% capacitance for X7R) > > >Is it safe to use 0402 pkg. instead of 0603? > > >Thanks, >Alex >------------------------------------------- >Alexander Shapira >Sr. PCB Designer >Leitch Technology Corp. >www.leitch.com <http://www.leitch.com> > >------------------------------------------------------------------ >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 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 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 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