Bi, the assumption is proximity of an isolated feature near a plane. A BGA doesn't match that very well at all. In the BGA ball field there will be lots of coupling between the immediately nearby balls. Steve. At 06:55 AM 9/20/2005 -0700, Bi Han wrote: >I guess I could use VIA formula (5*H*ln(4h/d)) to estimate the inductance, >since that applies to both via and bonding wire. It should works fine >generally for bump. > >Steve: why you think it does not make sense? > >Maybe its inductance is too low so that trace parasitics start to dominate >over. > >thanks, >Han > > > >steve weir <weirsi@xxxxxxxxxx> £º >Bi, the inductance of a single ball makes no real sense. If you do find=20 >such a formula, be careful to identify the assumptions about the rest of=20 >the path, and make sure that they also apply to your circumstances. > >Steve >At 05:25 AM 9/20/2005 -0700, Bi Han wrote: > >Hi: > > > >Is there any quick formula to estimate the solder ball inductance, given=20 > >the geometric size, such as diameter/height. > > > >thanks, > >Han > > > > > > > >--------------------------------- > > =D1=C5=BB=A2=C3=E2=B7=D1G=D3=CA=CF=E4=A3=AD=D6=D0=B9=FA=B5=DA=D2=BB=BE=F8= >=CE=DE=C0=AC=BB=F8=D3=CA=BC=FE=C9=A7=C8=C5=B3=AC=B4=F3=D3=CA=CF=E4 > > =D1=C5=BB=A2=D6=FA=CA=D6=A3=AD=CB=D1=CB=F7=A1=A2=C9=B1=B6=BE=A1=A2=B7=C0= >=C9=A7=C8=C5 > > > >------------------------------------------------------------------ > >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 > > > > ><http://cn.mail.yahoo.com>ÑÅ»¢Ãâ·ÑGÓÊÏä£ÖйúµÚÒ»¾øÎÞÀ¬»øÓʼþɧÈų¬´óÓÊÏä ><http://cn.zs.yahoo.com>ÑÅ»¢ÖúÊÖ£ËÑË÷¡¢É±¶¾¡¢·ÀɧÈÅ ------------------------------------------------------------------ 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