Hi, I would agree with the previous answers ... don't worry on the PCB performance to much, the degradation of the silicon is what you need to take care. On DRAM side it is not only the change in the OCD (output drivers), but also the refresh timings are getting quite short for 100°C. So you really need to do worst case corner simulations over the whole temperature range. I guess reliability is something you anyhow take a closer look for your temperature range .. regards Hermann EKH - EyeKnowHow Hermann Ruckerbauer www.EyeKnowHow.de Hermann.Ruckerbauer@xxxxxxxxxxxxx Veilchenstrasse 1 94554 Moos Tel.: +49 (0)9938 / 902 083 Mobile: +49 (0)176 / 787 787 77 Fax: +49 (0)3212 / 121 9008 Havermann, Gert schrieb: > Hi Barthi, > > Your question is how the characteristic impedance of the PCB is affected by > high temperatures (100°C)? > > The Temperature shouldn't have a big influence on impedance. The series > resistance will increase, but the result will just be higher losses. The > board sice will increase with temperature, but each differential pair will > just see fractions of this extra size, in my eyes not enough to worry about > impedance changes. > > I don't think you have to worry about temperature related impedance changes > on regular PCB at all, but I can't proof that with simulations or > measurements. > > BR > Gert > > > > -------------------------------------------------------------------------- > Absender ist HARTING Electronics GmbH & Co. KG; Sitz der Gesellschaft: > Espelkamp; Registergericht: Bad Oeynhausen; Register-Nr.: HRA 5596; > persönlich haftende Gesellschafterin: HARTING Electronics Management GmbH; > Sitz der Komplementär-GmbH: Espelkamp; Registergericht der Komplementär-GmbH: > Bad Oeynhausen; Register-Nr. der Komplementär-GmbH: HRB 8808; > Geschäftsführer: Torsten Ratzmann > -----Ursprüngliche Nachricht----- > > Von: si-list-bounce@xxxxxxxxxxxxx [mailto:si-list-bounce@xxxxxxxxxxxxx] Im > Auftrag von Barthi das > Gesendet: Mittwoch, 16. Dezember 2009 12:57 > An: si-list@xxxxxxxxxxxxx > Betreff: [SI-LIST] Effect of temperature on at 200C for DDR3/4 boards > > Hi, > > What is the effect of temperature (200C) on characteristic impedance at > DDR3/4 speeds and what the best way to control the impedance because of the > temp effect? Appreciate if anyone sends the literature related to the topic > > Thanks > Barthi > > > > > > ------------------------------------------------------------------ > 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.net > > List archives are viewable at: > //www.freelists.org/archives/si-list > > 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.net > > List archives are viewable at: > //www.freelists.org/archives/si-list > > 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.net List archives are viewable at: //www.freelists.org/archives/si-list Old (prior to June 6, 2001) list archives are viewable at: http://www.qsl.net/wb6tpu