Here is a way to ESTIMATE: 1. From frequency, determine skin depth (use an equation from any book); 2. Use R=(resistivity)*Length/Area, where Area is for the whole skin depth ring on the wire cross-section; 3. When there are gnd/pwr plane nearby, current is concentrated on one side of the wire. Multiply the R value from above by a factor of 1.53 (for round wire) to take account of this effect. I compared it with simulation, the result was generally within 10-15%. Pat -----Original Message----- From: Tegan Campbell [mailto:Tegan.Campbell@xxxxxxxxxxx] Sent: Thursday, March 27, 2003 11:26 AM To: si-list@xxxxxxxxxxxxx Subject: [SI-LIST] Question about power delivery to silicon in a BGA package All, What is a reasonable resistance to expect in wire bonds? Looking for one of those hated rules of thumb. I know the answer will vary according to too many things to list here, but I am getting information from a vendor that indicates there is 1 ohm(resistance only, inductance is a whole other ball of fun)per power/gnd bond from the package to the die. They are spice modeling, and the only answer I am getting to questions about the model is "trust us". This impedance is forcing me to bias the core voltage above spec on the outside of the package so the die sees the correct voltage. Problem is there are other IC's on the same power system. Any links/books/papers on the subject would be appreciated as well. Thanks in advance, Tegan Campbell ------------------------------------------------------------------ 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: http://www.freelists.org/webpage/si-list For help: si-list-request@xxxxxxxxxxxxx with 'help' in the Subject field List archives are viewable at: http://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: http://www.freelists.org/webpage/si-list For help: si-list-request@xxxxxxxxxxxxx with 'help' in the Subject field List archives are viewable at: http://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