# [SI-LIST] Re: Convergence problem after inserting detailed connector model

*From*: Yu Liu <yu_liu@xxxxxxxxxxxxx>*To*: julia.nekrylova@xxxxxxxxx*Date*: Thu, 19 Feb 2004 17:39:36 -0800

Hi, There is a myth about SPICE convergence problem like this one. Actually, for a strictly passive network consists linear RLC elements, the convergence problem should never occur - where is the nonlinearity in the network? The "time step too small" is likely caused by large local truncation error (LTE) rather than non-convergence. On the other hand, if the network is not strictly passive (even a linear RLCK network can exhibit non-passivity), and unfortunately we have seen this happens quite common in real cases by poor modeling, you can also run into this "time step too small" problem. Regards, Yu === Nekrylova, Julia wrote: >Hello, > > >I've added a detailed connector model to my Hspice deck and started >getting > >"internal timestep too small" error messages. Before that the connector >was represented just by > >RLGC matrix model. Tried different fixes: reduced transition times, set >initial conditions, > >tried gear method, put shunt conductances and capacitances. Some times >in the past Accurate=1 and > >Converge=4 worked for me, but this time nothing seems to help. > > > >What else I could try? I am pretty sure there are lots of people on the >list who had similar problems > >with their spice decks after adding sophisticated interconnect models. > >What could be the most popular solution in this case besides talking to >the connector company application engineer? > > > >Thanks a lot, > >Julia > > > > > > >------------------------------------------------------------------ >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 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 > > > > ------------------------------------------------------------------ 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 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

**References**:**[SI-LIST] Convergence problem after inserting detailed connector model***From:*Nekrylova, Julia

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- » [SI-LIST] Re: Convergence problem after inserting detailed connector model
- » [SI-LIST] Re: Convergence problem after inserting detailed connector model
- » [SI-LIST] Re: Convergence problem after inserting detailed connector model
- » [SI-LIST] Re: Convergence problem after inserting detailed connector model
- » [SI-LIST] Re: Convergence problem after inserting detailed connector model
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