question about op parameters in spectre

hello,

I have a question concerning dc op analysis. After completing the
simulation I would like to get some lx parameters' results for
transistors in my circuit (those familiar with hspice know these
parameters). I have worked with cadence environment before, where it
was possible to get a lot of parameters (including lx ones) when doing
OP("/M1","??") (from menu Results -> Plot -> DC operating points). My
current working environment doesn't show them. Does anyone know where
to enable displaying of those parameters?
Thanks for your help.

rgds.

 

[Riad KACED]

Hi There,

You have to toggle the 'save OP' switch when you run the DC/Tran for
example,
Your netlist should come with something like this in order fro the Op
parameters to be saved.
//
dcOp dc write="spectre.dc" maxiters=150 maxsteps=10000 annotate=status
dcOpInfo info what=oppoint where=rawfile
modelParameter info what=models where=rawfile
//

Chhers,

Riad.

 

Hello Riad,

Thanks for the reply. Actually I have this option enabled when doing
the simulation. The point is that the parameters' list I get lacks the
lx parameters only, the other parameters like c<xx> betaeff v<xx>
(where xx are terminal names for example gs) are present.

rgds.

 

[Riad KACED]

Hello Tempora !

You said in your original post "...those familiar with hspice know
these parameters ..."
I not familiar with hspice I'm afraid and I don't know these
parameters as a consequence, I'm very sorry :-(

I know however all the parameters dumped by Spectre after an OP
Analysis. You can find these paraeters i the folowing doc:
VirtuosoŽ Simulator Circuit Components and Device Models Manual :
$CDSHOME/doc/spectremod/spectremod.pdf

Report for example to the BSIM3V3 Operating-Point Parameters:
(My doc version is 6.2.1 December 2007), Chapter 21, Page 1161.
You will find all your wanted LX parameters :
--> ids (A) Resistive drain-to-source current (alias=lx4).
--> isub (A) substrate current (alias=lx50).
....

Good luck !

Riad.

 

[Riad KACED]

.... Last Post completion ...

In other words, the LX parameters are aliases in Spectre and you have
to go through the model document to know the true Spectre's parameter
names ...

Riad.

 

[Andrew Beckett]

Riad KACED wrote, on 05/23/08 23:40:

... Last Post completion ...

In other words, the LX parameters are aliases in Spectre and you have
to go through the model document to know the true Spectre's parameter
names ...

Riad.

Or type "spectre -h bsim4" (or whatever the model is) to see the parameters. In
the Operating Point Parameters section, you'll see lines such as:


8 vdsat (V) Drain-source saturation voltage (alias=lv10).
9 gm (S) Common-source transconductance (alias=lx7).
10 gds (S) Common-source output conductance (alias=lx8).

(it lists the alias at the end).

Andrew.