[SOLVED] Transient noise in OCEAN

[JoannesPaulus]

I am trying to run transient noise from an OCEAN script with the following settings

analysis( 'tran 
	  ?stop 	"100n" 
	  ?errpreset 	"moderate"  
	  ?method 	"gear2only"
	  ?noisefmax 	"1e9"  
	  ?noisefmin 	""  
	  ?noiseseed 	"7317"  
	  ?noisescale 	""  
	  ?noisetmin 	""  
	  ?noiseupdate 	"step"  
	  ?noiseonoff 	""  
	  ?noiseinst 	""  
)

but it appears that I can only get a simple transient analysis. Can OCEAN start a transient analysis?

 

[erikl]

Can OCEAN start a transient analysis?

Sure it can. But for a noise analysis, shouldn't you replace 'tran by 'noise ?

 

[JoannesPaulus]

Sure it can. But for a noise analysis, shouldn't you replace 'tran by 'noise ?

I was thinking of transient noise analysis not just a noise analysis.

 

[dick_freebird]

There is a tnoise checkbox in the more recent versions of the
PDK/Cadence combo I use. I think that setting may not be in
the Ocean script (no Ocean expert here). Might want to set up
a dummy AE window run where you know tnoise works by the
outcome, and Save Ocean Script that you can sift for any missing
switches.

Also find that since tnoise is kind of new, PDK does not have
anything close to proper noise scale factors - some of my
devices need 1000 range scaling to get what we see on the
bench on a time domain 'scope, despite being fitted to
traditional noise measurements and spectral results.

 

[JoannesPaulus]

Thank you dick_freebird! I started exactly the way you suggest (from an ocean script generated by AE where I tried my first simulation). The AE sim works fine but when I transfer the analysis option into ocean, it just runs a simple transient. Maybe, ocean is not ready for tnoise yet (I use ocean 5.1).
I'll post my discoveries here...

 

[dick_freebird]

Is there maybe anything in the CDS.log file that
echoes the stream from Choose Analysis? Or in the
netlist file? Something has to be telling Spectre, in
the foreground sims.

Maybe your Ocean is just invoking a stale Spectre
version that was pre-tnoise?

 

[JoannesPaulus]

Problem solved. The OCEAN installation the customer provided did not support transient noise. The workaround is including a file with the transient noise analysis in the netlist.