Si-folk, I am pinning-out a chip that will be used on a board that does not use via-in-pad technology. In order to place bypass caps in the 1mm ball field, I'll need to place 2 power balls in a row and two ground balls adjacent to the power balls, and drop an 0402 cap in between them. In order to maximize the number of caps, I could then keep adding a pair of power and gnd balls, and a cap. However, this will place all powers in one row and all grounds in aonther row and so the mutual inductance of the caps/vias in the power-delivery path will be increased. If I try to alternate power and ground, I will not be able to place as many caps, so how do I go about quantifying the trade-off between the two scenarios. (Scenario 1 is having more caps, but a topology in-which the mutual-inductance works against me. Scenario 2 is having fewer caps, but alternating occasionally so that the mutual- inductance works for me.) For this analysis, I'm estimating a 10 layer board and via inductance on the order of 0.9nH. I think this is reasonable. I would use 0.1uF 0402 caps. Here are pictures to clarify the question: P represents a power ball G represents a ground ball || represents an 0402 capacitor Scenario 1: P P P P P P P P P P P P || || || || || || || || || || || G G G G G G G G G G G G Scenario 2: P P P G G G P P P G G G || || || || || || || || G G G P P P G G G P P P Please point me to any relevant books/papers if you know of any. Thanks, Sarah ------------------------------------------------------------------ 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 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: 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