Hi: Thanks for your all's message. I think solder ball and bonding wire will have their self inductance. As friends pointed out, loop inductance is more complicated. Below is my opinion on the impact from environment. If there is matching resistor (to gnd) on the IO pad, thus the loop inductance should be simply adding those bonding wires and vias. Those routing traces were matched and should not be counted into loop inductance. Loop is "Driver - Bonding - trace - Bonding - resistor - Bonding - REF plane -Bonding - back to Driver". If there is no matching resistor on the IO pad, then the routing trace will impact SI severely, its inductance should be added into loop inductance. Above is my personal view, I've not read related topics very extensively. So, maybe someone can make it more clear. thanks, Han Aubrey_Sparkman@xxxxxxxx wrote: Han, Inductance requires knowledge of the complete loop or an assumption of the complete current path. Where is the other solder ball? Aubrey Sparkman Enterprise Engineering Signal Integrity Team Dell, Inc. Aubrey_Sparkman@xxxxxxxx (512) 723-3592 -----Original Message----- From: si-list-bounce@xxxxxxxxxxxxx [mailto:si-list-bounce@xxxxxxxxxxxxx] On Behalf Of Bi Han Sent: Tuesday, September 20, 2005 8:55 AM To: weirsi@xxxxxxxxxx; List` Si Subject: [SI-LIST] Re: Re: Flip Chip Solder Ball inductance 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 £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 --------------------------------- ÑÅ»¢Ãâ·ÑGÓÊÏä£ÖйúµÚÒ»¾øÎÞÀ¬»øÓʼþɧÈų¬´óÓÊÏä 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 --------------------------------- Yahoo! for Good Click here to donate to the Hurricane Katrina relief effort. ------------------------------------------------------------------ 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