Inductance is a property of a current loop. Most probably you can approximate the bump simply as a small section of a segment, as part of a much longer path. Consider also that once soldered, the balls of the BGA will not be spherical any more, but resemble columns thinner at the center and wider at the pads. For how I solved exactly this problem you can check my thesis under the 'Literature' page: E. Di Lorenzo,"Caratterizzazione Elettromagnetica di Packages Ultraminiaturizzati Applicati a Memorie Flash-EEPROM", E. Di Lorenzo Thesis, Politecnico di Milano, 1998. It is in Italian but you have figures to look at and Google translator for the text..
BGA Bump Geometry
Posted - Nov 07 2015 : 22:13:34
