Thanks Scott for your idea. We will experiment on this and keep updated.... Thanks Sanjeev On Thu, Oct 9, 2014 at 5:29 PM, Scott McMorrow <scott@xxxxxxxxxxxxx> wrote: > Sanjeev > > Yes, this is quite possible to reference to a "universal ground". You just > have to create a new pec plane in the design that is removed from the > surrounding structures so that it does not couple, and reference ports to > this plane. At it's corners it can be strapped with large resistors to > provide isolation and a DC connection. You then have to insure that there > is a very large boundary, so that stray fields remain in the design, and > use a high resolution solution to reduce noise in the full wave solution. > > It's a pain, but is quite possible. > > regards, > > Scott > > > Scott McMorrow > Teraspeed® Consulting - A Division of Samtec > 16 Stormy Brook Rd > Falmouth, ME 04105 > (401) 284-1827 Business > http://www.teraspeed.com > > On Thu, Oct 9, 2014 at 1:21 AM, Sanjeev Gupta <skgupta.sanjeev@xxxxxxxxx> > wrote: > >> is it possible to extract Vss and Vcc s-parameter respect to ideal >> reference? I doubt, any tool can do this kind of s-parameter extraction. >> if such s-parameter extraction is not possible. do you suggest to use RLC >> models of VCC and VSS based on quasi-static extraction (using Q3D) for SSN >> problem solution. >> >> Thanks >> >> >> On Wed, Oct 8, 2014 at 9:47 PM, Iliya Zamek <dmarc-noreply@xxxxxxxxxxxxx> >> wrote: >> >> > Hi Naresh, >> > Steve described in details many reasons why receiver might see a noise >> > when you applied in-phase noise to Vss and Vcc. It is also important to >> > know some more details about your experiments to make a conclusion. >> Whether >> > you were using oscilloscope, or receiver to measure output jitter and >> > noise, and how you applied noise to Vss and Vcc. In addition to Steve >> > observation, different "modulation sensitivity" of Vss and Vcc, the >> > pre-driver to the jitter contribution, and just simple conversion of >> > waveform' shift to the jitter, - all might contribute to the output >> jitter >> > and noise. I agree with you that I/O delay respect to the Vss >> "disturbance" >> > also one of the reason of remaining noise. >> > I also agree with you that it is good to extract both Vss and Vcc >> respect >> > to ideal reference, which is not so easy to simulate. However, if you >> can, >> > there is even more important reason to do so. If you have other signals >> > switching along with you measured, these others will contribute through >> > common Vss to the Vss noise. So, all depends on details how you applied >> > noise and did measurements. >> > Thank you.Iliya >> > On Tuesday, October 7, 2014 11:50 PM, Naresh Dhamija < >> > naresh.dhamija@xxxxxxxxxxxxx> wrote: >> > >> > >> > Hi Iliya, >> > >> > >> > I understand that different blocks inside IO will convert the in phase >> > noise to differential noise and will cause jitter within the IO, but at >> the >> > output of IO pad w.r.t noise vss, I see some noise, I guess it is >> because >> > of finite delay within the output stage of IO . Is this correct? >> > >> > >> > >> > If it is so, then my follow up question is: >> > >> > In the complete system simulation, when we plug package and board >> > s-parameter models, it is good to have both vddio and vss extracted >> w.r.t >> > ideal ground rather than only vddio extracted which will only have >> > differential noise of vddio with its local vss where common noise of >> vddio >> > and vss is missed out. >> > >> > >> > >> > Regards >> > >> > Naresh >> > >> > >> > >> > *From:* Iliya Zamek [mailto:i_zamek@xxxxxxxxx] >> > *Sent:* Wednesday, October 08, 2014 12:38 AM >> > *To:* naresh.dhamija@xxxxxxxxxxxxx; si-list@xxxxxxxxxxxxx >> > *Subject:* Re: [SI-LIST] Single ended Noise OR Differential Noise >> > >> > >> > >> > Hi Naresh, >> > >> > >> > >> > Your observation is correct. The impact of PDN noise on on-chip signals >> > timing and logic levels noise is different. The impact on I/O Jitter is >> > more complex. >> > >> > The impact on logic levels' noise does not depend on noise frequency and >> > I/O signal frequency interrelationship, but impact on I/O' Jitter does. >> You >> > might want to see the results of research of impact noise on Jitter in a >> > paper (and references) by Google: "On-chip Jitter and system Power >> > Integrity", I. Zamek, Designcon 2012 >> > >> > >> > >> > Also, there are two effects to consider at I/O Jitter analysis: impact >> on >> > Pre-Driver and impact on output Buffer. Impact on Pre-Driver contribute >> > mainly on Jitter, the impact on Buffer contributes on both, Jitter and >> > Logic levels' noise. You might see the research and experiments on I/O >> > jitter in reference #16: >> > >> > Zhe Li, Iliya Zamek, Peter Boyle, âFPGA IO Timing Variations with SSO >> > Noise,â DesignCon 2008 >> > >> > >> > >> > Thank you. >> > >> > >> > >> > Iliya Zamek >> > >> > >> > >> > >> > >> > On Tuesday, October 7, 2014 6:10 AM, Naresh Dhamija < >> > naresh.dhamija@xxxxxxxxxxxxx> wrote: >> > >> > >> > >> > Hi folks, >> > >> > I am doing power noise analysis on a system that uses SSTL IO buffers. I >> > am seeing the ripple on the IO output signal - such that during hi state >> > IO output signal follows the noise whatever is on the vddio and during >> low >> > state, IO output signal follows the noise on the vss. Observing this >> > phenomenon, I purposely forced IN PHASE single ended noise to both >> vdddio >> > and vss of almost the same frequency as of data rate but uncorrelated >> with >> > data rate. Since noise forced to vddio and vss are IN PHASE so >> > Differential Noise measured between vddio and vss at each instant shows >> > zero noise. But still I see jitter on the edges because of finite rise >> and >> > fall times, the initial low level and final high level for a transition >> > from low to hi are not always same. Does this mean that along with >> > differential noise, single ended noise on power and ground also cause >> > jitter to IO driver. >> > >> > Regards >> > Naresh >> > ------------------------------------------------------------------ >> > 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 forum is accessible at: >> > http://tech.groups.yahoo.com/group/si-list >> > >> > 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 forum is accessible at: >> > http://tech.groups.yahoo.com/group/si-list >> > >> > 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 forum is accessible at: >> > http://tech.groups.yahoo.com/group/si-list >> > >> > 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 >> > >> > >> > >> >> >> -- >> Thanks >> Sanjeev >> >> ------------------------------------------------------------------ >> 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 forum is accessible at: >> http://tech.groups.yahoo.com/group/si-list >> >> 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 >> >> >> > -- Thanks Sanjeev ------------------------------------------------------------------ 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 forum is accessible at: http://tech.groups.yahoo.com/group/si-list 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