Giuseppe, Does your BGA Package have a metal "die paddle" or "flag" that is floating? A trick we did at a previous company was to wirebond all the ground pads (and the signal pin of interest) to ground. This method has the added benefit of including some wirebond inductance in your signal which is important. Aubrey Sparkman=20 Enterprise Engineering Signal Integrity Team Dell, Inc.=20 Aubrey_Sparkman@xxxxxxxx=20 (512) 723-3592 The Greatest Pleasure in Life is Doing what People say can't be done... -----Original Message----- From: si-list-bounce@xxxxxxxxxxxxx [mailto:si-list-bounce@xxxxxxxxxxxxx] On Behalf Of Giuseppe DABUNDO Sent: Friday, April 14, 2006 9:50 AM To: si-list@xxxxxxxxxxxxx Subject: [SI-LIST] TDR measurement Hi All, I'm currently working to measure parasitics of a BGA Package's nets (RLC) by TDR measurements.My package is mounted on a board and i performed two measure :a first one on a board with empty socket and the second one with the package inside the socket.At the moment I have measured only the value of capacitance using a method suggested in some application notes of TDA Systems. http://www2.tek.com/cmswpt/tidownload.lotr?ct=3DTI&cs=3DApplication+Note&= ci=3D 3049&lc=3DEN&wt=3D480&wtwi=3D3049&wtla=3DEN&wtty=3DTI&wtsty=3DApplication= +Note&wtpt=3D DOWNLOAD&wtsize=3D866+KB&wtver=3D1.0&wtcat=3Dtektronix&wtnbrp=3D0&wtti=3D= TDR+Techn iques+for+Characterization+and+Modeling+of+Electronic+Packaging+ My problem is that i haven't a 'short' either at level board and inside the package(it's a major problem because i can't connect wire bond to ground);in other words i have all net open-ended. I would like to know if another method to measure L and R without a 'short' reference exists . Thanks Giuseppe ------------------------------------------------------------------ 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: =20 //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 =20 ------------------------------------------------------------------ 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