Steve, Where does the 31.9nH/Square come from? Best regards, John =20 --------------------------------------- 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=20 January 2005. You can find the presentation in whole on both the=20 X2Y, and Teraspeed web=20 sites: http://www.x2y.com/bypass/method/does_position_matter.pdf,=20 and http://www.teraspeed.com/publications.html Note that they apply=20 for specific circumstances of calculating spreading inductance=20 between a power ring, and a surrounding bypass capacitor ring. This=20 would also work for a single Vdd / Vss pair. However for more=20 complex pin arrays, you really need to solve the plane. Tools from=20 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 =3D3D u0 / 2=3DF0 * H * (( ln( R2/R1 ) * KPERF ) + >ln( R3/R2 )) >- u0 =3D3D 31.9nH/square >- H =3D3D cavity height >- R3 =3D3D radius from die center to bypass cap ring >- R2 =3D3D radius from die center to via field edge >- R1 =3D3D 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. >=3D20 > >-----Original Message----- >From: si-list-bounce@xxxxxxxxxxxxx [mailto:si-list-bounce@xxxxxxxxxxxxx] =3D >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 =3D >dimensionless >(i.e. nH/sq) and not a function of the distance between two points, =3D >rather a >function of aspect ratio of the plane - L x W. So, the size of the =3D >plane >isn't what affects spreading inductance, but its shape does. Are these =3D >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: =3D20 > //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 > =3D20 > >------------------------------------------------------------------ >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: =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 ------------------------------------------------------------------ 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