The Designer's Guide Community
Forum
Welcome, Guest. Please Login or Register. Please follow the Forum guidelines.
Mar 28th, 2024, 5:44pm
Pages: 1
Send Topic Print
Effective length of capacitance in less than or equal to zero (Cadence Spectre) (Read 4146 times)
Estimulo
New Member
*
Offline



Posts: 1

Effective length of capacitance in less than or equal to zero (Cadence Spectre)
Oct 29th, 2016, 1:00am
 
Hello Everyone,

While simulating a design of 3:8 decoder, spectre is producing an error as :

Error found by spectre during initial setup.
   ERROR (CMI-2215): I0.I6.I0.M1: The effective length of capacitance is less than or equal to zero.

I have tried changing width of M1 and transistors present in instances I0 and I6.

Please tell me, how can it be resolved.

Thanks
Back to top
« Last Edit: Oct 29th, 2016, 3:15am by Estimulo »  

error_001.png
View Profile   IP Logged
Geoffrey_Coram
Senior Fellow
******
Offline



Posts: 1998
Massachusetts, USA
Re: Effective length of capacitance in less than or equal to zero (Cadence Spectre)
Reply #1 - Oct 31st, 2016, 10:47am
 
I think there's something wrong with your setup.  You shouldn't be getting those warnings about "'nf' is not a valid parameter"

I wonder if you're using a netlist from one PDK with a model library from another PDK.
Back to top
 
 

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



Posts: 3

Re: Effective length of capacitance in less than or equal to zero (Cadence Spectre)
Reply #2 - Jun 2nd, 2018, 5:27am
 
Hey i am facing the exact same issue with the same library ,
could someone please help?
Back to top
 
 
View Profile   IP Logged
Abhi_iitm
New Member
*
Offline



Posts: 3

Re: Effective length of capacitance in less than or equal to zero (Cadence Spectre)
Reply #3 - Jun 2nd, 2018, 5:28am
 
Geoffrey_Coram wrote on Oct 31st, 2016, 10:47am:
I think there's something wrong with your setup.  You shouldn't be getting those warnings about "'nf' is not a valid parameter"

I wonder if you're using a netlist from one PDK with a model library from another PDK.


I am facing the same issue though i am using the pdk for the same library
kindly help,
Regards
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: Effective length of capacitance in less than or equal to zero (Cadence Spectre)
Reply #4 - Jun 2nd, 2018, 6:45am
 
It would help somewhat if you said which PDK (and models) you were using - info such as the foundry, process node, and ideally any version number for the PDK or model files.

That will significantly increase the chance of somebody being able to help you.

Regards,

Andrew.
Back to top
 
 
View Profile WWW   IP Logged
Abhi_iitm
New Member
*
Offline



Posts: 3

Re: Effective length of capacitance in less than or equal to zero (Cadence Spectre)
Reply #5 - Jun 2nd, 2018, 6:57am
 
it is UMC_18_CMOS

These are the directory details indicating exact model:
G-9FD-MIXED_MODE_RFCMOS18-1.8V_3.3V-1P6M-MMC_ \
UM180FDKMFC00000OA-FDK-Ver.A02_PB \
/UM180FDKMFC00000OA_A02_DESIGNKIT \
/UM180FDKMFC00000OA_A02_PB/UMC_18_CMOS
Back to top
 
 
View Profile   IP Logged
Geoffrey_Coram
Senior Fellow
******
Offline



Posts: 1998
Massachusetts, USA
Re: Effective length of capacitance in less than or equal to zero (Cadence Spectre)
Reply #6 - Jun 4th, 2018, 7:11am
 
Is "n_18_mm" a mismatch model? If you look in the model files, can you determine if it is a subckt or model card? If you use regular (not mismatch) models, does the simulation work?

(You probably should not post the actual model files, since this is UMC's IP and it would likely violate an NDA.)
Back to top
 
 

If at first you do succeed, STOP, raise your standards, and stop wasting your time.
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.