Re: OPA891 / OPA2891 Model Needed
Very good advice. You can also, with
advantage, do both; save in both locations, so that in 2027 you
won't need to recall which? schematic directory the model is in.
On 2024-12-20 14:45, Andy I via
groups.io wrote:
Keep that model
file in the same directory with your schematic - or move it to one
of your User-defined Lib. Search Path folders.
--
OOO - Own Opinions Only
Best Wishes
John Woodgate
Keep trying
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Re: OPA891 / OPA2891 Model Needed
Just in case it was not obvious already -
?
Use LTspice's "opamp2" symbol with this model, after making the change to the model file.
?
Change the name next to the symbol from "opamp2" to "OPA891".
?
Also add this line:
? ? .lib OPA891_Movel_V1p1.lib
to your schematic.? Keep that model file in the same directory with your schematic - or move it to one of your User-defined Lib. Search Path folders.
?
Andy
?
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Re: OPA891 / OPA2891 Model Needed
Let us know if you encounter any problems with that model.? I did not try it yet.
?
Andy
?
?
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Re: OPA891 / OPA2891 Model Needed
On Fri, Dec 20, 2024 at 09:18 AM, <info@...> wrote:
TI is publishing the OPA891 model only for their TINA program.
It is a SPICE model.
?
TINA-TI can use either generic SPICE models, or models using their own format which only work in their program.? Fortunately, this one is a SPICE model.? ?In that respect, there should be nothing to convert.
?
I also understand that the TINA model uses non-standard pin order to assign nodes to its opamp symbol so that needs to be fixed.
That is true - to the extent that the pin-order is really a "standard".? There is a customary pin-order that most op-amp SPICE models use, but not all.? This is one of the exceptions.
?
There are multiple ways to "fix" that.? The easiest, is to open the OPA891 SPICE? model in a text editor (LTspice has a pretty good text editor built-in), and change this line:
? ? .subckt OPA891 IN+ IN- OUT V+ V-
to this:
? ? .subckt OPA891 IN+ IN- V+ V- OUT
While you are at it, also delete the very last line in the file:
? ? .END
because it has no place being in a SPICE model.? Then save the file.
?
Andy
?
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OPA891 / OPA2891 Model Needed
TI is publishing the OPA891 model only for their TINA program. I understand there is a procedure to extract the TINA model information and make a LTSpice-compatible model.
I also understand that the TINA model uses non-standard pin order to assign nodes to its opamp symbol so that needs to be fixed.
I struggle to install a new spice model into my installation, mainly because I do it very seldom and forget how to do it when I need to do it again.? Has someone already come up with a working LTSpice model of the 0PA891 that I can install in my system?
Thanks!
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I suppose that Rds depends on die temperature,
too, so large signal Rds is a thicket, not a value.
On 2024-12-20 12:25, Andy I via
groups.io wrote:
But RON is defined for linear region right??
Even in the FET's linear region, it is nonlinear.? It is
unlikely that a JFET or MOSFET has an Rds that is actually
linear, in the so-called linear region.? It "bends", even
there.
?
But if you found a FET whose Rds was strictly linear, then
there would be no difference between small-signal and
large-signal Rds.
?
Andy
?
--
OOO - Own Opinions Only
Best Wishes
John Woodgate
Keep trying
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On Thu, Dec 19, 2024 at 09:41 PM, <abanindra.kumarmandal.ece24@...> wrote:
But RON is defined for linear region right??
Even in the FET's linear region, it is nonlinear.? It is unlikely that a JFET or MOSFET has an Rds that is actually linear, in the so-called linear region.? It "bends", even there.
?
But if you found a FET whose Rds was strictly linear, then there would be no difference between small-signal and large-signal Rds.
?
Andy
?
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On Thu, Dec 19, 2024 at 10:03 PM, <abanindra.kumarmandal.ece24@...> wrote:
What will be the expression for RON then??
Either one.? They would be the same.? (But unlikely.)
?
Andy
?
?
?
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What will be the expression for RON then??
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On Thu, Dec 19, 2024 at 09:41 PM, <abanindra.kumarmandal.ece24@...> wrote:
But RON is defined for linear region right??
Not necessarily.
?
If it is linear, then you know that the small-signal and large-signal definitions would be the same, so there would be no question.
?
Andy
?
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But RON is defined for linear region right??
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Re: Separate from .CKT for .lib file
On Thu, Dec 19, 2024 at 09:00 PM, Mirza wrote:
I got a .CKT file and .lib file of photodiode and transimpedance amplifier.
I know how to make spice model from these files.
However, I want to separate transimpedance amplifier part from the .CKT file or .lib file.
Is it possible to separate?
It's impossible to say anything about your files or models, without seeing them.
?
But I will say that you probably can separate the photodiode part of the model from the amplifier part of the model.? Usually they can easily be separated.
?
By the way, filename extensions do not make any difference.? Maybe they mattered if they were made for a different simulator, but LTspice doesn't care whether it is .CKT or .LIB or .MOD or .Nonsense.
?
The lib file has many raw data which are unknown to me.
That is puzzling and I don't know what you mean.? Is the model encrypted?? If it is, then much of it would look like confusing data.? It is usually easy to tell when a model is encrypted by looking for the telltale identifiers.? Let's assume that it is not.
?
Perhaps the model uses tables, which could be extensive.
?
I am confused that you say you know how to make a SPICE model from those files, yet some of their contents are unknown.? That doesn't make much sense.
?
Andy
?
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Re: Separate from .CKT for .lib file
Anything is possible if you know what you are doing. Why not post your files by uploading them to the \Temp folder. That way we are in a better position to help you. Best method is to combine the into a ".zip" file. DO NOT use any other form of compression. Thanks.
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Separate from .CKT for .lib file
Hi
I got a .CKT file and .lib file of photodiode and transimpedance amplifier.
I know how to make spice model from these files.
However, I want to separate transimpedance amplifier part from the .CKT file or .lib file.
Is it possible to separate?
The lib file has many raw data which are unknown to me.
?
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Re: Placing a Symbol and its .cir "Manually" into a schematic
I finally saved a copy of the symbol in the local (“.”) folder, one of the two I now have access to.
?
?
toggle quoted message
Show quoted text
From: [email protected] < [email protected]> On Behalf Of
Tony Casey
Sent: Thursday, December 19, 2024 2:29 PM
To: [email protected]
Subject: EXTERNAL: Re: [LTspice] Placing a Symbol and its .cir "Manually" into a schematic
?
On 19/12/2024 22:29, Bell, Dave via groups.io wrote:
You should be able to bring up the current folder from F2 by selecting it from the "Top Directory" drop-down selector at the top of the dialogue.
--
Regards,
Tony
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Re: LTspice 24.1 Beta Available Now
On 19/11/2024 03:32, j.a.morgan.gm via
groups.io wrote:
Hi.? Just downloaded, looking forward to trying it out
tomorrow.
Writing here as I noticed this beta includes better path support
for libraries, right after writing about the use of environment
variables (as suggested a couple years ago by somebody) in
another post.? It's probably too late for this release but maybe
there is a better or at least parallel way that allows better
portability.? See my post, here.
So glad to see that AD/LT are still giving LTspice some love
with new releases. I'd be so dissapointed if it were canned in
favor of the AD/SIMPLIS EE Oasis. As much as I do like SIMPLIS's
speed (used it with TI and standalone) I always choose LTspice
over it, the propretary models are so trustworthy.
LTspice already supports environmental variables though the
operating system calls it uses. Unfortunately, though, it doesn't
acknowledge this if you try to view a model file linked by:
.lib ModelFileName.sub
.. when used with, for example, an environmental variable called
%MyModelLibs% that is listed in Settings > Search Paths >
Library Search Paths. However, in practice, LTspice still finds
ModelFileName.sub, provided it really does exist in the folder
pointed to by %MyModelLibs%, when an analysis is run.
Rather unhelpfully, LTspice tells you that %MyModelLibs% doesn't
exist when you add it to Settings > Search Paths > Library
Search Paths, but you can override this and tick "Add it anyway".
--
Regards,
Tony
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Re: LTspice 24.1 Beta Available Now
Beta, Betta, Bettastill.
On 2024-12-19 22:28, Andy I via
groups.io wrote:
On Thu, Dec 19, 2024 at 05:15 PM, BRUCE108 wrote:
The link to the beta release appers to be broken. Is this
intentional or just an accident?
It is not precisely a broken link.? I think the Beta
version was taken down a couple of weeks ago, probably while
Analog Devices works out the bugs.
?
I did not see any confirmation of that, but I think it is
the most likely reason why.
?
I have heard nothing about a newer Beta version yet, so I
guess it's just wait and see until ADI has one ready for the
masses.
?
Andy
?
?
--
OOO - Own Opinions Only
Best Wishes
John Woodgate
Keep trying
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Re: Placing a Symbol and its .cir "Manually" into a schematic
On 19/12/2024 22:29, Bell, Dave via
groups.io wrote:
Long explanation below, but here’s what I am
trying to do:
In a local folder where all my personal
LTspice projects and libs reside, I have
Potmet.asy
Potmet.cir
As below, I cannot access those from within
LTspice where I’m editing a model.
I can add .include Potme.cir without errors,
but how can I insert Potmet.asy, since I can’t pull it up under
F2?
?
?
Within the last few days, I have “lost”
access to my local \Documents\LTspiceXVII subfolders.
This appears to be due to the Company
migrating users to OneDrive, with some possible (temporary?)
sync errors.
?
From windows explorer, I have
\Documents\LTspiceXVII\MySymbols, but that folder and apparently
none of the others appear in OneDrive.
?
In LTspice Tools > sym & lib search
paths, I only have “.” and
“C:\Users\dbell5\Documents\LTSpice\LTspiceXVII”
When I try to add
C:\Users\dbell5\Documents\LTSpice\LTspiceXVII\MySymbols it
throws an error, saying that path does not exist.
Adding it anyway, or NOT, when I go to F2 and
pull down the search paths, the added paths are missing.
You should be able to bring up the current folder from F2 by
selecting it from the "Top Directory" drop-down selector at the top
of the dialogue.
--
Regards,
Tony
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Re: LTspice 24.1 Beta Available Now
On Thu, Dec 19, 2024 at 05:15 PM, BRUCE108 wrote:
The link to the beta release appers to be broken. Is this intentional or just an accident?
I think the Beta version was taken down a couple of weeks ago, probably while Analog Devices works out the bugs.
?
I did not see any confirmation of that, but I think it is the most likely reason.
?
I have heard nothing about a newer Beta version yet, so I guess it's just wait and see until ADI has one ready for the masses.
?
Andy
?
?
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If I want to
plot RON vs Vds is nmos in ltspice... Should I do d(Vds)/d(Id) or
VDS/ID?... Please help as whether RON is a large signal parameter
or small signal??
You should use d(Vds)/d(Id) because it is a non-linear function.
--
Regards,
Tony
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John Woodgate
Bell, Dave
Tony Casey