The Designer's Guide Community
Forum
Welcome, Guest. Please Login or Register. Please follow the Forum guidelines.
Apr 28th, 2024, 5:48pm
Pages: 1
Send Topic Print
speeding up co-simulation of VerilogA + devices (Read 2919 times)
schehrazi
Community Member
***
Offline



Posts: 45
University of CA, LA
speeding up co-simulation of VerilogA + devices
May 20th, 2006, 7:58pm
 
For the following simulation, I am using Cadence Spectre.

Assume we have a system which is modeled in VerilogA. Now, I want to add a low pass filter somewhere in this system. I have two options, 1. make a VerilogA description of that filter 2. make it with Ls and Cs taken from analogLib
It seems that simulating the system with LC filter takes longer than the system with the VerilogA filter. This makes sense to me but is this speed reduction fundamental? I mean is there anyway to speed up the simulation of the VerilogA system with the LC filter in it instead of using the VerilogA filter?

Thank you so much
Back to top
 
 
View Profile   IP Logged
Geoffrey_Coram
Senior Fellow
******
Offline



Posts: 1998
Massachusetts, USA
Re: speeding up co-simulation of VerilogA + device
Reply #1 - May 24th, 2006, 4:38am
 
Does your system have a lot of Ls?  They add an extra matrix row to the set of equations, so this could be an issue for large circuits -- though I doubt you'd notice it in a small circuit.

It's also possible that the equations are scaled differently in Verilog-A than with the Ls and Cs, such that the tolerances are harder to satisfy one way or another; ie, if you have a time constant sqrt(1/(LC))  you could get the same constant by doubling L and halving C, but the current in the inductor would be changed by a factor of two and thus the circuit might take fewer iterations to converge (current error less than abstol).
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.