Dimiter, I believe the process is IBM 130 nm. With regards to the energy the spikes are roughly 2 ns long and the clock frequency is 100 MHz. Thanks, /Mikhail ----- Original Message ----- From: "Dimiter Popoff" <dp@xxxxxxxxxxx> To: <matusov@xxxxxxxxxxxx> Cc: <si-list@xxxxxxxxxxxxx> Sent: Friday, March 03, 2006 10:42 AM Subject: Re: [SI-LIST] Effects of overshoot/undershoot on long-term reliability > I guess it would depend not just on the peak voltage but on > the energy in that peak (i.e. peak area). > I don't know what technology the DSP is - overshoots > like this should matter somewhere about 130 nm and below, > if older, chances are you will face no problems (but > we'll know for sure after several years :-). > If 130 nm and below, it would really be an interesting > experiment to have one board constantly on until it fails - after > days, months or years ? Really interesting, if you make such an > experiment please keep us posted. > > Dimiter > > > ------------------------------------------------------ > Dimiter Popoff Transgalactic Instruments > > http://www.tgi-sci.com > ------------------------------------------------------ > > > > -------Original Message------- > > From: Mikhail Matusov <matusov@xxxxxxxxxxxx> > > Subject: [SI-LIST] Effects of overshoot/undershoot on long-term reliability > > Sent: Mar 03 '06 17:34 > > > > Dear experts, > > > > I designed a card based on the ADI TS201 TigerSHARC EZ-KIT evaluation board > > schematics. The TS201 has 2.5V 3.3V-tolerant I/Os . On this board it is > > directly connected to a 3.3V Micron SDRAM. Unfortunately, we had not > > simulated this interface before going into the layout. When we did we found > > that there is a huge overshoot on SDRAM read reaching almost 5V at the DSP > > pins. Our SI subcontractor recommends adding series terminations at the > > SDRAM pins. At this point it would mean major PCB redesign. I pulled an > > EZ-KIT card and captured the read cycle to verify the simulation results and > > found that the board behaves exactly as in simulation, i.e. the DSP chip is > > constantly subjected to this huge overshoot. However, the board works fine. > > So, I was wondering how I could estimate the risk of leaving the design as > > is? > > > > > > Thanks, > > ======================= > > Mikhail Matusov > > Hardware Design Engineer > > Square Peg Communications > > Tel.: +1 (613) 271-0044 ext.231 > > Fax: +1 (613) 271-3007 > > http://www.squarepeg.ca > > > > > > ------------------------------------------------------------------ > > 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: //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