No, this will not give you any kind of jitter information.

If you're looking at the pss-td results, then this will only be a single period of the fundamental frequency. If you're looking at the pss-tran (or whatever it is called), then this is just the initial transient used for partial settling before the shooting interval starts. In either case, these do not include any noise sources.

In pnoise, the noise sources are added as small signal noise sources around each of the devices in the circuit. It will then compute the transfer functions of these to the output (including any noise folding effects) giving you the total noise at the output of the circuit in a desired band. You can also strobe the noise using tdnoise.

All of this is discussed in Ken's paper on jitter and phase noise in the Analysis section (see links at the top of the site's web page). Also, there is a "jitter" mode for pnoise now (introduced in IC5141) which allows you to measure jitter more conveniently/directly for both driven and autonomous circuits.

Spectre does now have a transient noise analysis (as from MMSIM60 onwards), but in general you would usually be better off using pnoise/tdnoise if you can (it would normally be quicker and more accurate). There have been discussions to this effect in this forum before, if my memory serves me correctly. Transient noise analyses are best for looking in a qualitative way where noise results in some large signal effect, particularly in non-periodic circuits (or at least circuits where the period is not constant).

Regards,

Andrew.

The concept of peak-to-peak jitter is not well defined in this context. The noise sources are Gaussian, which are unbounded. And as such, the resulting jitter is unbounded. The best you can do is give the likelihood that a particular bound is exceeded.

-Ken

You should always integrate the noise power (V²/Hz) and not the noise voltage. So you can either square the noise voltage or use the noise power directly, Spectre computes both.

-Ken

At a minimum, you must take the square root after integrating to convert V² to V. Then dividing through by the slew rate will give you units of seconds.

-Ken

I am not familiar with the peak option on the PNoise form, but as I said before, it cannot be the peak jitter because Gaussian jitter is not bounded. Peak jitter really only makes sense when the jitter is deterministic.

You should avoid the flicker noise (remove it before integrating). Jitter due to flicker noise is not defined.

-Ken

I wondered whether you might be using the pss results instead of the pnoise/tdnoise results (from another post you made in another thread).

It sounds as if you're doing Direct Plot->Main Form, and then you'd get a choice of pss and pnoise. If you're interested in the noise, looking at the pss results will not give you the information you're after, since that is the large signal results (as I explained earlier), before the noise sources are enabled. It's the pnoise tab which will give you access to the pnoise or tdnoise results.

I think you need to read the SpectreRF documentation (user guide, theory guide)  in cdsdoc, as I think your understanding of what each analysis does is a little misplaced.

Regards,

Andrew.

If you use standard PNoise rather than the strobed PNoise, then you are including noise that occurs at times other than when the signal is crossing its threshold. Noise produced when the output is all the way high or all the way low does not contribute to jitter, but often dominates the noise that standard PNoise measures.

Actually, I went back and took a closer look at my notes, and I think you should be able to include the flicker noise. Before you do though, make sure you have carefully resolved the flicker noise. I often see people use equal frequency point spacing during their PNoise analysis with an insufficient number of points to accurately resolve the flicker noise corner, and when they do the integration they get a highly inflated number for the flicker noise contribution.

-Ken