I believe that the telegrapher's equation is fine assuming that the line = is long enough that the "ends" of the line do not through off the calculatio= n. The point I was trying to make is the following: 1) If you divide a structure and model it as two separate pieces, a. you need to consider the coupling between the two pieces 2) If you model the structure as one complete piece, a. this is already inherently included in the solution Regards, Patrick -----Original Message----- From: si-list-bounce@xxxxxxxxxxxxx [mailto:si-list-bounce@xxxxxxxxxxxxx]On Behalf Of Jayaprakash Sent: Tuesday, December 09, 2003 6:11 AM To: si-list@xxxxxxxxxxxxx Subject: [SI-LIST] Re: I have a question related package parasitic extraction Hello Patrick, Then the same argument should hold good even for Transmission line model described using telegrapher's equation? By telegrapher's equation, Transmission line has uniform RLGC per unit length. The output voltage is given by Vo =3D exp(-gamma*Line_length)*vin (for a perfectly matched system) Is this description of Transmission line not really scalable? (Going by the explanation given below, I expect over projection of loss for longer lines than actually it is) Thanks and regards, Jayaprakash. --- Patrick Zilaro <pzilaro@xxxxxxxxxxxx> wrote: > KD, > > There is nothing wrong with the commercial solver. > Even if you were to > simulate a planar structure such as a trace, you > would see that the "parts" > do not add up to the "whole". For example, if you > simulated a 5mm trace and > a 10mm trace using the exact same stack-up, etc. you > would find the > following: > > 1) capacitance -> 2*5mm trace should be pretty equal > to 10mm trace > 2) (ac) resistance -> 2*5mm trace should be less > than the 10mm trace > 3) inductance -> 2*5mm trace should be even more > less than the 10mm trace > > This is because each segment of the structure > interacts with the rest of the > segments. So be careful, when you break up a > problem, especially since you > are introducing error on the optimistic side (where > you usually would prefer > to be on the pessimistic side). > > Regards, > > Patrick > > -----Original Message----- > From: si-list-bounce@xxxxxxxxxxxxx > [mailto:si-list-bounce@xxxxxxxxxxxxx]On Behalf Of KD > KIM > Sent: Monday, December 08, 2003 3:59 PM > To: si-list@xxxxxxxxxxxxx > Subject: [SI-LIST] I have a question related package > parasitic > extraction. > > > Dear all, > I have a question and be happy to write to you. > > I have simulation the structure composed of only one > bonding wire and one > lead, > using FEM commercial solver, Ansoft Spicelink like > below for extraction > parasitic values, > R, L, and C. > > I have simulated for below three cases. > > 1. the structure contained only one bonding wire > 2. the structure contained only one lead > 3. the structure composed of one wire and one lead > > I think the value for case 3 equal to the values > case 1 added case 2. > But the result was not. The difference was about 16% > for the Resistance. > Of course, other parasitic values also have some > differences considerably. > Is this difference resulted from the defect of the > FEM commercial solver? > I want to know that what do you think about it? > Please reply to my e-mail. =3D=3D=3D=3D=3D Balachandran Jayaprakash Celestijnenlaan, 3/61, 3001, Heverlee, Leuven, Belgium. Mobile: +32-472-630120 ________________________________________________________________________ BT Yahoo! Broadband - Save =A380 when you order online today. Hurry! Offe= r ends 21st December 2003. The way the internet was meant to be. http://uk.rd.yahoo.com/evt=3D21064/*http://btyahoo.yahoo.co.uk ------------------------------------------------------------------ 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 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 ------------------------------------------------------------------ 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 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