Giuseppe- If you can't establish a current loop for whatever reason I wonder how you expect to determine an inductance value. When you send the incident TDR pulse into the package net a return current path must exist in order to determine the inductance. This is not required for your capacitance measurement since voltages as opposed to currents are involved. Regard, -Ray Raymond Anderson Senior Signal Integrity Staff Engineer Product Technology Department Advanced Package R&D Xilinx Inc. -----Original Message----- From: si-list-bounce@xxxxxxxxxxxxx [mailto:si-list-bounce@xxxxxxxxxxxxx] On Behalf Of Giuseppe DABUNDO Sent: Friday, April 14, 2006 7:50 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=20 (RLC) by TDR measurements.My package is mounted on a board and i=20 performed two measure :a first one on a board with empty socket and the=20 second one with the package inside the socket.At the moment I have=20 measured only the value of capacitance using a method suggested in some=20 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=20 the package(it's a major problem because i can't connect wire bond to=20 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=20 '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: //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