John, this is the permeability of free space. It is an observed constant behavior. Best Regards, Steve. At 07:30 AM 9/25/2006, Hill, John wrote: >Steve, > >Where does the 31.9nH/Square come from? > >Best regards, > >John > > > > >--------------------------------------- >The information in this email and attachments hereto may contain >legally privileged, proprietary or confidential information that is >intended for a particular recipient. If you are not the intended >recipient(s), or the employee or agent responsible for delivery of >this message to the intended recipient(s), you are hereby notified >that any disclosure, copying, distribution, retention or use of the >contents of this e-mail information is prohibited and may be >unlawful. When addressed to Takata customers or vendors, any >information contained in this e-mail is subject to the terms and >conditions in the governing contract, if applicable. If you have >received this communication in error, please immediately notify us >by return e-mail, permanently delete any electronic copies of this >communication and destroy any paper copies. >--------------------------------------- >-----Original Message----- > >From: si-list-bounce@xxxxxxxxxxxxx [mailto:si-list-bounce@xxxxxxxxxxxxx] >On Behalf Of steve weir >Sent: Tuesday, September 19, 2006 12:28 AM >To: Sirisha.Godavarthy@xxxxxxxxxxxx; Tim.J.Nash@xxxxxxxxxxxxx; silist >Subject: [SI-LIST] Re: Spreading Inductance > >Tim, those equations come from a presentation I made to the SCVEMC >January 2005. You can find the presentation in whole on both the >X2Y, and Teraspeed web >sites: http://www.x2y.com/bypass/method/does_position_matter.pdf, >and http://www.teraspeed.com/publications.html Note that they apply >for specific circumstances of calculating spreading inductance >between a power ring, and a surrounding bypass capacitor ring. This >would also work for a single Vdd / Vss pair. However for more >complex pin arrays, you really need to solve the plane. Tools from >IBM, KAW, Ansoft, or Sigrity are all capable of that task. > >Steve. >At 05:57 AM 9/18/2006, Sirisha Godavarthy wrote: > >Hi Tim, > >I got some info regarding spreading inductance. > >Hope it helps. > > > >Plane spreading inductance: > > > >- L of PLANE_CAVITY =3D u0 / 2=F0 * H * (( ln( R2/R1 ) * KPERF ) + > >ln( R3/R2 )) > >- u0 =3D 31.9nH/square > >- H =3D cavity height > >- R3 =3D radius from die center to bypass cap ring > >- R2 =3D radius from die center to via field edge > >- R1 =3D radius from die center to pkg power / ground attachments. > >- KPERF scaling factor for perforation in via field > >* For perforations small compared to wavelength area ratio > > > >Thanks&Regards, > >Sirisha. > > > >Thanks&Regards, > >Sirisha. > >=20 > > > >-----Original Message----- > >From: si-list-bounce@xxxxxxxxxxxxx >[mailto:si-list-bounce@xxxxxxxxxxxxx] = > >On Behalf Of Nash, Tim J (EHCOE) > >Sent: Friday, September 15, 2006 7:56 PM > >To: silist > >Subject: [SI-LIST] Spreading Inductance > > > > From what I have gathered, spreading inductance of a plane is = > >dimensionless > >(i.e. nH/sq) and not a function of the distance between two points, = > >rather a > >function of aspect ratio of the plane - L x W. So, the size of the = > >plane > >isn't what affects spreading inductance, but its shape does. Are these >= > >true > >statements? I want to make sure I understand this correctly. > >Best Regards, > >Tim > > > > > >-- Binary/unsupported file stripped by Ecartis -- > >-- Type: application/x-pkcs7-signature > >-- File: smime.p7s > > > > > >------------------------------------------------------------------ > >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 ------------------------------------------------------------------ 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