How to turn off flicker noise in Spectre?

You can do this by disabling the parameters in the models (could be done via an include file which used "alter" to turn off the noise parameters, I think - I've not tried - or definitely by editing the model files).

You can also turn of the noise contributions for specific devices altogether on Simulation->Options->Analog (only recently added though, in the last year if my memory is correct).

Also you can look at Results->Print->Noise Summary to see which noise contributors have an effect or are the biggest contributors to the noise - so you can see how much comes from flicker, how much from shot, how much from thermal etc.

Not exactly what you're after - but may be an alternative. By all means contact Customer Support if you would like spectre enhanced to provide what you're asking for.

BTW, I thought that Eldo allowed you to disable flicker noise for transient noise (which you can also do in spectre, if you don't specify noisefmin), but wasn't aware of this being possible for normal noise analysis - at least not without modifying the model parameters in a similar fashion to with spectre.

Regards,

Andrew.

Hello Andrew,

     Thank you very much, your reply is really helpful.

     Best Regards!

     Jacki

Hello Andrew,

     I cannot find alter in Cadence Spectre ADE, does the "alter" belong to ocean script?

     Thank you.

     Best Regards!

     Jacki

Jacki,

alter is a spectre language statement. You can find out more from a terminal window by typing "spectre -h alter". The idea is that you could have an include file (say, specified as a file from the Model Libraries setup in ADE). Give the file a suffix of ".scs" so it's interpreted in spectre syntax (avoids needing to add the line "simulator lang=spectre") and then you can enter things in spectre's own syntax.

You could then do things like:

myAlt1 alter mod=nch param=kf value=0
myAlt2 alter mod=pch param=kf value=0

and so on. Now you'd have to make sure you pick the right models, and the right flicker noise parameter (which would depend on the actual model type used), but this probably should work (I've not tried, as I said). 

Whether it's worth the bother, and whether it really tells you any more than the noise summary does, is another matter. You can also use the results browser to plot the noise contribution from any device, including the breakdown of what the noise source is in that device (so plot the noise at the output coming from the flicker noise for a specific device, for example, versus frequency).

Regards,

Andrew.

Hello Andrew,

 Thank you very much to teach me use the alter. I have turned off the flicker noise now. But I think for PSP model, it is a little different from BSIM3v3 model. Maybe in BSIM3v3 model, only setting kf = 0 is OK to turn off flicker noise. For PSP model, I also need to set   

+  noi_scale = 0
+  noia_mul  = 0
+  noib_mul  = 0
+  noic_mul  = 0

Then I turn off the flicker noise.

 Jacki

Those don't look like parameters for any of the psp models that I can see in spectre (e..g "spectre -h psp103" or "psp1021" etc). Maybe they're aliases (although not documented). They look closer to the bsim4  parameters, but even then they're called noia, noib, noic (no _mul). So what you've done seems a bit surprising...

That said, I didn't do any experiments - as I said, maybe they are aliases.

Andrew.

Eldo does now offer the ability to run both flicker and thermal noise, or select either one or the other only for either the small signal or transient noise sims.