The Designer's Guide Community
Forum
Welcome, Guest. Please Login or Register. Please follow the Forum guidelines.
Mar 29th, 2024, 8:32am
Pages: 1
Send Topic Print
AC analysis in spectre (Read 92 times)
Gp
Community Member
***
Offline



Posts: 35

AC analysis in spectre
May 16th, 2017, 4:24am
 
Hi All,

I want to run AC analysis of Low pass filter with cadence spectre. With transient analysis, it's working fine But during AC analysis following error generated:

******************************************************
AC Analysis `frequencySweep': freq = (1 Hz -> 100 MHz)
******************************************************
DC simulation time: CPU = 11.999 ms, elapsed = 42.51 ms.

Opening the PSF file /home_ei/pdubey_ei/Desktop/gp_test/VAMS_examples/LPF/amscf.raw/frequencySweep.ac
...
ncsim: *F,INTERR: INTERNAL EXCEPTION
Observed simulation time : 0 FS + 2
-----------------------------------------------------------------



My spectre.scs file is following:

simulator lang=spice

.AC DEC 5 1 100e6


simulator lang=spectre

myopts options duplicate_subckt=warning
myinfo info what=oppoint where=rawfile
spectre options diagnose=detailed debugstepdrop=yes simstat=detailed debug=yes duplicateinstance=warning duplicatemodel=warning


So, Kindly give the solution.

Thank you


Back to top
 
 
View Profile   IP Logged
Ken Kundert
Global Moderator
*****
Offline



Posts: 2384
Silicon Valley
Re: AC analysis in spectre
Reply #1 - May 16th, 2017, 9:32am
 
You should contact Cadence when you have an internal error.

An internal error is a reaction to some unusual or unexpected condition. To work around it, you should try to identify anything you are doing that is unusual and then get rid of that thing to see if the error goes away.

-Ken
Back to top
 
 
View Profile WWW   IP Logged
Geoffrey_Coram
Senior Fellow
******
Offline



Posts: 1998
Massachusetts, USA
Re: AC analysis in spectre
Reply #2 - May 16th, 2017, 1:32pm
 
I'd get rid of the two options statements and the info, to start (I'm particularly curious about "spectre" as a possible keyword and the name of your second options statement).

And I'd re-write your .ac line in Spectre syntax.

Not that Spectre shouldn't be able to handle it, but along the lines of Ken's suggestion, eliminate anything weird.
Back to top
 
 

If at first you do succeed, STOP, raise your standards, and stop wasting your time.
View Profile WWW   IP Logged
AMS_ei
Community Member
***
Offline



Posts: 67

Re: AC analysis in spectre
Reply #3 - May 19th, 2017, 11:42pm
 
spectre doesn't normally use ".ac" since that is the archaic SPICE syntax rather than spectre's own more regular syntax
Back to top
 
 
View Profile   IP Logged
Andrew Beckett
Senior Fellow
******
Offline

Life, don't talk to
me about Life...

Posts: 1742
Bracknell, UK
Re: AC analysis in spectre
Reply #4 - May 28th, 2017, 9:53am
 
It's also a good idea to mention which version of the simulator you're using, in case this is a known problem. In this specific case there's not enough information to be going on (it's pretty unlikely that all ac simulations fail because that would be picked up prior to the software being released).

However, if you're running an old version of spectre, I'd always suggest trying a recent version just in case the specific issue you're hitting has been solved subsequently.

I was able to run an AC simulation using a simple circuit together with  your other statements in SPECTRE161 with no problem at all.

Regards,

Andrew.
Back to top
 
 
View Profile WWW   IP Logged
Pages: 1
Send Topic Print
Copyright 2002-2024 Designer’s Guide Consulting, Inc. Designer’s Guide® is a registered trademark of Designer’s Guide Consulting, Inc. All rights reserved. Send comments or questions to editor@designers-guide.org. Consider submitting a paper or model.