Re: [SI-LIST] : via capacitance

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From: Scott McMorrow (scott@vasthorizons.com)
Date: Tue Apr 11 2000 - 08:00:45 PDT


Gus,

There you go getting into the details again.
One of these days I'm just going to have to fly out
there and see what a connector guy does.

best regards,

scott

--
Scott McMorrow
Principal Engineer
SiQual, Signal Quality Engineering
18735 SW Boones Ferry Road
Tualatin, OR  97062-3090
(503) 885-1231
http://www.siqual.com

apanella wrote:

> Is this 0.3 pF Assuming that there isn't a current return path (ground) via > near by? > > If there is a return path (ground) via near by... one might want to know > the pitch between the vias before using the 0.3 pF value. > > For example.. like the vias you might have for the through hole tails of a > connector.. when using the connector to connect two PCBs. > > Best Regards, > _gus > apanella@enteract.com > > ----- Original Message ----- > From: Ritchey Lee <leeritchey@earthlink.net> > To: <si-list@silab.eng.sun.com> > Sent: Monday, April 10, 2000 9:15 AM > Subject: Re: [SI-LIST] : via capacitance > > > I have done many experiments to determine the capacitance value of vias. > A 13 mil diameter via, 100 mils long has approximately .3 pF of capacitance. > Your traces will average about 3 pF per inch of > > length. The small value of the via capacitance will not be detectable at > edge rates slower than 100 pSEc. > > > > Lee > > > > Sunil Kumar wrote: > > > > > Dear all SI experts. > > > > > > I am using a multilayer board having the following stack-up: > > > > > > LAYER1 TOP LAYER (CONDUCTOR) > > > LAYER2 GND > > > LAYER3 CONDUCTOR > > > LAYER4 CONDUCTOR > > > LAYER5 VCC > > > LAYER6 GND > > > LAYER7 CONDUCTOR > > > LAYER8 CONDUCTOR > > > LAYER9 GND > > > LAYER10 BOTTOM LAYER (CONDUCTOR) > > > > > > A signal trace is going from layer7 to layer8. A through-hole via is > used. > > > The via is having pads on layers 1,7,8,10. There are antipads on the > power > > > planes. Is there any formula/tools to calculate the exact capacitance of > > > the via?? How can I measure it in the board?? > > > > > > Sunil Kumar > > > Research Engineer > > > C-DOT > > > INDIA > > > > > > **** To unsubscribe from si-list or si-list-digest: send e-mail to > majordomo@silab.eng.sun.com. In the BODY of message put: UNSUBSCRIBE si-list > or UNSUBSCRIBE si-list-digest, for more help, put HELP. > > > si-list archives are accessible at http://www.qsl.net/wb6tpu > > > **** > > > > > > > > > > **** To unsubscribe from si-list or si-list-digest: send e-mail to > majordomo@silab.eng.sun.com. In the BODY of message put: UNSUBSCRIBE si-list > or UNSUBSCRIBE si-list-digest, for more help, put HELP. > > si-list archives are accessible at http://www.qsl.net/wb6tpu > > **** > > > > > > **** To unsubscribe from si-list or si-list-digest: send e-mail to majordomo@silab.eng.sun.com. In the BODY of message put: UNSUBSCRIBE si-list or UNSUBSCRIBE si-list-digest, for more help, put HELP. > si-list archives are accessible at http://www.qsl.net/wb6tpu > ****

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