Ihsan, I agree. If you take measurements at 5 different portal (spyhole) locations, you'll get 5 distinct results. This kind of noise is highly location-dependent. For the static-0 output, location is a dominating factor (it's mostly crosstalk). For the static-1 output, location can be secondary because the disturbance may be dominated by variation of the IO power system voltage within the device. With static-1, you're seeing a combination of IO power system disturbance as well as crosstalk. As for a "too much noise" metric, this is complicated. Looking for an erroneous logic level is a good place to start, but often the thing that causes a system to fail is timing variation of the IO interfaces (which may occur long before a logic glitch). SSO noise can be thought of as adding jitter to the various signals in the interface, reducing timing margin. -mark -----Original Message----- From: si-list-bounce@xxxxxxxxxxxxx [mailto:si-list-bounce@xxxxxxxxxxxxx] On Behalf Of Ihsan Erdin Sent: Thursday, August 03, 2006 10:03 AM To: james.f.peterson@xxxxxxxxxxxxx Cc: fasig.jonathan@xxxxxxxx; si-list@xxxxxxxxxxxxx Subject: [SI-LIST] Re: SSN analysis? One thing I can add to the 2nd method is about the selection of the steady-state IOBs for the worst case SSN effect. That calls for choosing the quite buffer(s) farthest from a ground/Vdd pin for low/high steady-state analysis. Regards Ihsan On 8/3/06, Peterson, James F (EHCOE) <james.f.peterson@xxxxxxxxxxxxx> wrote: > > hello Jonathan -=3D20 > > Do you want to estimate the amount of current rushing in or out of the > Altera part, or do you want to analyze the impact of this current surge? > > If it's the amount of I, then it is straight forward - but don't use the > old "hang a capacitor on the buffer" approach. Think transmission line > and represent the t-line with a resistor equal to Zo and another > resistor for Zs (source impedance) and then tie them to rails (note : > there might be other resistors in the path depending on your HSTL term > scheme). Solving for I (E/Rtotal) seems to line up very well with SI > simulators that can measure the in-rush current (if you have one you can > just simulate to get the answer). then take this answer and multiply > times the # of outputs switching at the same time for total surge > current. > > If it's the second question (what does this current surge do to my > Altera's internal PDS?), then I can't help as much (sorry). There is a > technique that's sometimes called the "portal method", that is used to > look inside the device. Attach a scope to a quiet buffer driving high. > Switch all the outputs from a 0 to a 1 and note the noise spike on the > scope (the buffer is driving 1 so you are looking at the Vdd rail). Then > have the quiet buffer drive a logic 0 (Vss rail) and switch all of the > outputs from a logic 1 to 0 and note the noise spike. I've used this > method on large devices and it seems to work ok, but it needs a fast > scope.=3D20 > > The missing part of this is when will the part fail. This is usually > defined as when a quiet buffer toggles because of all the noise...I'd > try to get Altera to help you with this. > > Hope this helps. > > Jim > Honeywell > > -----Original Message----- > From: si-list-bounce@xxxxxxxxxxxxx [mailto:si-list-bounce@xxxxxxxxxxxxx] > On Behalf Of Fasig, Jonathan L. > Sent: Thursday, August 03, 2006 9:45 AM > To: si-list@xxxxxxxxxxxxx > Subject: [SI-LIST] SSN analysis? > > We are working on SSN analysis for an application that will have 600 > HSTL I/O's on an Altera Stratix-II GX130. Is there anyone in this > community who has done (or is currently doing) similar work? > > jf > > ------------------------------------------------------------------- > > Jonathan Fasig Email: = fasig.jonathan@xxxxxxxx=3D09 > Mayo Foundation > 4001 41st Street NW=3D20 > MSC Sn 2-132 Phone: (507) 538-5464 > Rochester, MN 55901 Fax: (507) 284-9171 > ------------------------------------------------------------------ > 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: =3D20 > //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 > =3D20 > ------------------------------------------------------------------ > 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 > > > ------------------------------------------------------------------ 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