Somehow when you add label in Smith Chart Plot window, it's really difficult to move label marque on smith chart and sometimes impossible to edit label captions.Hope someone fixes it in next release.
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Smith Chart Bug
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How to choose the operating point displayed in IC6.1.6-64b.101 ?
Hi all,
I'm currently use the virtuoso version IC6.1.6-64b.101 and in a previous version I could change and choose which operating point parameter I would to be displayed like Cgs, Region, gm, ... on schematic window. For that I did "Edit/Component display" in schematic window and it was good.
But now, with this version "Edit/Component display" doesn't exist anymore ! and I don't find the way to display these parameters.
The only way found is to use calculator "op" swicth, select my component, the parameter and the result is printed in the calculator.
But I cannot do that in complex shematic with lot of mos inside !
If someone has the solution ? :)
Thanks in advance for your help.
Rgds,
Chris
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How to use BSIM-CMG models to build and simulate FinFET circuits
Hi All,
I need to simulate FinFET based circuits
I have BSIM-CMG codes and models from http://www-device.eecs.berkeley.edu/bsim/?page=BSIMCMG_LR
this includes veriloga files.va and files.include and model card.nmos files
I tried several methods to add these in Cadence, but still something missing
so I am asking about the right way to add such files to enable circuit simualtion.
if any one managed to do this before, could help.
Thanks
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PSPICE Error Message
I am not a prolific user of Pspice and have just received received a PSice file from an external contractor. The scematic loads ok but when I try to run the file I get the following error message :
"(ORCAP-15051) Current schematic that you are editing is not in the smulation hierarchy. Do you wish to continue?"
If I try to continue the simualtion does not run.
Can anyone please advise me as to what I am doing wrong!!
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top side test points
Hi
I'm trying to manually add test points to my pcb. I can add the bottom ones fine. But I have a track/cline on the top side of the pcb that never goes to the bottom side. Usually I just add a thruvia from the top to the bottom in the 9.2 package which is the test point. All of our pcb testpoints are picked up from the bottom side.
In 16.6 I have a thru via made and added in the "TestPrep Paramters - Padstack Selections"...'Bottom side Testpoint and Top Side Testpoint"....for the "THRUVIA" row I add a via that goes from both sides of the pcb.
Yet when I go to place it on a track all I see in the command window is the message...."last pick: xxx,xxx". And there is no test point.
Any ideas what I'm missing?
TIA!!
I'm trying to manually add test points to my pcb. I can add the bottom ones fine. But I have a track/cline on the top side of the pcb that never goes to the bottom side. Usually I just add a thruvia from the top to the bottom in the 9.2 package which is the test point. All of our pcb testpoints are picked up from the bottom side.
In 16.6 I have a thru via made and added in the "TestPrep Paramters - Padstack Selections"...'Bottom side Testpoint and Top Side Testpoint"....for the "THRUVIA" row I add a via that goes from both sides of the pcb.
Yet when I go to place it on a track all I see in the command window is the message...."last pick: xxx,xxx". And there is no test point.
Any ideas what I'm missing?
TIA!!
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Place a symbol on the cursor?
I want the symbol to be put on the cusor, just like move or manual place, with the ability to rotate. Then place by a user pick.
I know I could use axlDBCreateSymbol and axlEnterPoint, this would not allow a rotation. Is there another solultion?
Thanks,
Jerry
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Assembly/Silkscreen text mirrored on bottom side
The Assembly and Silkscreen text is mirrored on the bottomside of the PCB. How can in correct this?
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Spectre temperature coefficient oddness
We have a tool that makes subcircuit models of passive components (an integrated inductor in this example). It can now produce models that have temperature dependence, and in that case the output model includes components with linear temperature coefficients. There are subcircuit models in both Spectre and Spice format.
When I run Spectre and Spice (ngspice in particular) to play back the models at the nominal temperature (25C), the inductor characteristics are identical. The problem is that the inductor characteristics differ when I use a temperature (125C in this case) that is different than nominal.
In trying to isolate the problem, I converted the Spectre model into a form that writes out the temperature dependence explicitly. According to the Spectre Components and Device Models Manual, for something like a resistor, the temperature dependence has this form:
Reff = Rnom * (1 + tc1*(T-tnom))
The temperature dependence of inductors and capacitors is similar. I changed each line in the Spectre model according to this equation. For example, I changed this:
R8 (n5 n6) resistor r=27.588830e3 tc1=-2.219425e-03
to this:
R8 (n5 n6) resistor r=27.588830e3*(1+ -2.219425e-03*(temp-tnom))
When I run Spectre on this model with explicit temperature dependence, it matches Spice exactly (and hence does not match Spectre with the temperature coefficient).
I have verified this behavior with two different versions of Spectre, one fairly old and one new.
Oddly, when I use Spectre's info statement to examine the components, Spectre shows that both the explicit-temperature and temperature-coefficient versions have identical effective component values! (And both differ from the nominal temperature case, so the temperature is definitely having an effect.) So I seem to be somehow getting identical circuit topologies, identical component values, and differing electrical behavior, with the explicit-temperature version exactly matching a different tool.
At this point I'm at a loss. Clearly I must be misunderstanding something, because this seems far too basic to be broken. I've been fiddling with it for three days though and can't figure out what's going on.
I've attached a tarball that contains the two Spectre netlists demonstrating the problem, along with the Spice-format model, a run script that invokes Spectre and compares the effective component values, and the S-parameter outputs from the Spectre runs and also from my Spice run. There's a README.txt that describes the files in the tarball, and also a plot showing the inductor electrical behavior for the two Spectre models and how the explicit version agrees with Spice. The exact versions of Spectre that I tried are also in the README.txt file.
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Error while using 'asiAddAnalysis' function
I wrote the following SKILL code in "XYZ.il"
procedure(xyz() asiAddAnalysis( 'analog
?name 'XYZ ?
prompt "XYZ" ?fieldList list( asiCreateAnalysisField( ?name 'from ?prompt "from" ?value "0" ?row 1 ?column 1 )
asiCreateAnalysisField( ?name 'to ?prompt "to" ?row 1 ?column 2) asiCreateAnalysisField( ?name 'by ?prompt "by" ?row 1 ?column 3) ) ?optionList list( asiCreateAnalysisOption( ?name 'XYZ1 ?value "1e-4" ) asiCreateAnalysisOption( ?name 'XYZ2 ?value "1e-6" ) ) ) )
when I load and run the procedure 'xyz()' from CIW window i get the fllowing error :
*Error* (Default-reader-method) generic:asiGetName class:symbol
when i run 'xyz()' from skill prompt i get :
*Error* eval: undefined function - asiAddAnalysis
The CDS log says that analog.cxt and oasis.cxt did get loaded.
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oscillation frequency estimate using harmonic balance
Hi,
I am working on a crystal oscillator. I want to estimate frequency pulling over temperature caused by circuit (excluding crystal). I am looking at something around 0.01ppm/C level or less. It takes too much time to use shooting mehod. So I use harmonic balance to figure out oscillation frequency. It gives good resulton 2ppm frequency pulling (matches my hand calculation). But I do not know if 0.01ppm frequency pulling can be simulated by harmonic balance. What parameters do I need to tighten?
The oscillator XIN and XOUT have small sinusoidal swing. Not much harmonics at all.
Thank you in advance!
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Adding ADE Analysis using SKILL code
I want setup transitent analysis for 1u stop vlaue using SKILL code ) . I was trying to that using asiGetAnalysis and asiAddAnalysisField or asiAddAnalysisFieldVal.
It would be really helpful if you could kindly give me an example SKILL code that does the following :
1) set the simulator to "spectre"
2) setup transient analysis for 1u
In docementation I have found this asiSetFormFieldVal( r_form ?stop "5n" ). How do get the r_form handle for analysis.
Thanks
cADEUser
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