Re: Looking for ideal fully differential amplifier spice model
Here is the thread I found on fully diff OpAmps
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Re: Looking for ideal fully differential amplifier spice model
On Sun, Dec 22, 2024 at 08:46 AM, John Woodgate wrote:
Yes, because it's quite easy, and probably cheaper, to use 2 or 3 sections of a quad opamp to make a good balanced-in/balanced-out circuit.
XSPICE models are minimalistic and designed for speed. Complex models would slow simulations to a crawl. In this case the "XSPICE way" for making a fully differential OpAmp creates a model with limitations and the odd "feature" it doesn't care if inputs or outputs are swapped.
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Re: Looking for ideal fully differential amplifier spice model
A model that would work for both LTspice and any Spice 3 simulator. The model will also be used in mixed-mode simulations with XSPICE models.?
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Re: Whither 4053_tercio.asy
Hello John W.
I have uploaded the complete Robertugo/SwitchAna files from my personal archive.
It appears to contain all that is needed for the 4051, 52 and 53 parts.
I hope this helps.
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All for now
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Sent:?Saturday, December 21, 2024 at 2:40 PM
From:?"John Waugaman via groups.io" <jwaugaman@...>
To:[email protected]
Subject:?[LTspice] Whither 4053_tercio.asy
The analog switch library "SwitchAna.Lib" makes reference to various symbols (e.g.? "4053_tercio.asy") and phrases like "The model needs two params: Vcc & Vel see the circuit example..".? Where might I find these?
John
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Re: Looking for ideal fully differential amplifier spice model
Yes, because it's quite easy, and probably
cheaper, to use 2 or 3 sections of a quad opamp to make a good
balanced-in/balanced-out circuit.
On 2024-12-22 13:31, Tom via groups.io
wrote:
The generic Spice model would be usable in LTspice or Spice
programs that support XSPICE. I found 2 on this forum from 2011
using various search terms.
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There are many choices for an generic OpAmp with SE output
but it seems few for DE output.
--
OOO - Own Opinions Only
Best Wishes
John Woodgate
Keep trying
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Re: Looking for ideal fully differential amplifier spice model
Tom,
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Maybe you did not understand my question.
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Are you looking for a model to run in LTspice, or are you looking for a model to run in XSPICE (or other SPICE programs)?
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The ideal op-amp models that come with LTspice have single-ended outputs so they are not what you are looking for -- but my point is that it is an LTspice-unique model making it something that would not run in XSPICE or other SPICE programs.
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So -- here it is again -- are you looking for a model that runs in LTspice, or are you looking for a model that runs in XSPICE?? If someone made a modification of the LTspice ideal op-amp model with differential outputs, would that satisfy your needs, knowing that it does not play with XSPICE?
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Andy
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Re: Looking for ideal fully differential amplifier spice model
The generic Spice model would be usable in LTspice or Spice programs that support XSPICE. I found 2 on this forum from 2011 using various search terms.
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There are many choices for an generic OpAmp with SE output but it seems few for DE output.
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Re: Looking for ideal fully differential amplifier spice model
On Sat, Dec 21, 2024 at 11:09 PM, Tom wrote:
Looking for ideal fully differential amplifier spice model for XSPICE simulations.
I am a little confused about the request.? Does that mean you want a model that will be used in XSPICE?? Or one for LTspice that behaves similarly to a model you already have for XSPICE?
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If it is for LTspice, can it be for LTspice only (using LTspice-unique constructs)?
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Andy
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Looking for ideal fully differential amplifier spice model
Looking for ideal fully differential amplifier spice model for XSPICE simulations. The one I have based on the XSPICE "gain" code model doesn't have any CMRR or care if outputs are swapped. Anything based on dependent sources would be good.
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* XSPICE Fully Differential OpAmp
.subckt opamp inp inn outp outn in_offset=0 gain=300e3 out_offset=0
aint %vd(inp inn) %vd(outp outn) amp
.model amp gain (in_offset='in_offset' gain='gain' out_offset='out_offset')
.ends opamp
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The SE output OpAmp using the same structure works fine...
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Re: Whither 4053_tercio.asy
Andy,
I had to do a deeper search in my archive, but found them.
I uploaded a newer zip file with the missing asy files.
Mike
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Re: Whither 4053_tercio.asy
Story of my life! That's why I usually use
'JMW' rather than 'JW', but at one time there were at least
three people called John Michael Woodgate (only very distantly
related, if at all) in Britain.
On 2024-12-21 23:36, Andy I via
groups.io wrote:
On Sat, Dec 21, 2024 at 06:31 PM, John Woodgate wrote:
I can live without them,
...
Sorry!? That was the other John W (Waugaman).
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--
OOO - Own Opinions Only
Best Wishes
John Woodgate
Keep trying
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Re: Whither 4053_tercio.asy
On Sat, Dec 21, 2024 at 06:31 PM, John Woodgate wrote:
I can live without them, ...
Sorry!? That was the other John W (Waugaman).
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Re: Whither 4053_tercio.asy
I can live without them, and I'm sure Andy
will provide all the help you need.
On 2024-12-21 23:25, Andy I via
groups.io wrote:
On Sat, Dec 21, 2024 at 06:17 PM, Mike Fraser wrote:
I found the files in my offline LTspice storage location.
Files are uploaded as 4053_tercio.zip.
Thanks, Mike.
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I don't know if it matters (to John W), but your uploaded
.zip file is missing the symbols "1To2.asy" and "switchana.asy".
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Andy
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--
OOO - Own Opinions Only
Best Wishes
John Woodgate
Keep trying
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Re: Whither 4053_tercio.asy
On Sat, Dec 21, 2024 at 06:17 PM, Mike Fraser wrote:
I found the files in my offline LTspice storage location.
Files are uploaded as 4053_tercio.zip.
Thanks, Mike.
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I don't know if it matters (to John W), but your uploaded .zip file is missing the symbols "1To2.asy" and "switchana.asy".
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Andy
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Re: Whither 4053_tercio.asy
John & Andy,
I found the files in my offline LTspice storage location.
Files are uploaded as 4053_tercio.zip.
I have no idea if the files are current with the latest Bordodynov library.
You will simply need to try the example and see if it works.
Mike?
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Re: Whither 4053_tercio.asy
A much older version of "SwitchAna.Lib" was also mentioned in this 2008 message thread:
but it appears they did not successfully upload the library containing that and other files.
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It looks like they may have uploaded the whole thing to a different Yahoo!Group which does not exist anymore.? There may be some hope of finding it again but don't hold your breath.? (At one time I downloaded the files from the extinct LTspiceDocs group, but I might not be able to find them today.)
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That 2008 message thread also mentions "LTspicePlus", which I think was another large collection of user-contributed models and files to use with LTspice.? I think you can find LTspicePlus at the LTwiki website, here:
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Scroll down to "New Updated Version".
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I think LTspicePlus downloads as a self-extraction .exe file - so it is really a .zip file with self-unzipping code included.? Maybe that librarry contains all the missing information you seek.
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Andy
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Re: Whither 4053_tercio.asy
On Sat, Dec 21, 2024 at 02:40 PM, John Waugaman wrote:
The analog switch library "SwitchAna.Lib" makes reference to various symbols (e.g.? "4053_tercio.asy") and phrases like "The model needs two params: Vcc & Vel see the circuit example..".? Where might I find these?
It's difficult to trace back in time, 7 years later.? But the library file "SwitchAna.Lib" was uploaded and mentioned in this thread:
Unfortunately, that .Lib file was the only thing uploaded then.? Bordodynov was the uploader, and he is still occasionally active in this group so maybe he can fill in the gaps.
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Regarding the missing parameters, just define them yourself, maybe something like this:
? ? .param Vcc=10? ?(use your actual voltage)
? ? .param Vel=1? ?(guessing that Vel is a relative speed setting where 1 = nominal)
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For the LTspice symbol, I suggest drawing it yourself.? So, for the 4053, draw the symbol for a CD4053, see how the pins line up with the .SUBCKT definition (".Subckt 4053_tercia I inh xio yio xoy"), and you might be good to go.
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That .Lib file apparently came from somewhere else, and the one .Lib file might be the only thing that made it into this group's Files.? I suggest carefully reading the thread above about the CD4053 to see if you can find any clues.? Otherwise, wait to hear from Bordodynov himself.
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Andy
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The analog switch library "SwitchAna.Lib" makes reference to various symbols (e.g.? "4053_tercio.asy") and phrases like "The model needs two params: Vcc & Vel see the circuit example..".? Where might I find these?
John
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Re: OPA891 / OPA2891 Model Needed
On Sat, Dec 21, 2024 at 12:20 PM, <info@...> wrote:
I added "OPA891" to Value 2 in both my OPA891 and OPA2891 symbols and now my sims all work using my user defined locations.
Just to be clear -
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Adding "OPA891" as the Value2 attribute has nothing to do with putting your symbols and models in your user-defined locations.
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Andy
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Re: OPA891 / OPA2891 Model Needed
Problem solved:
I added "OPA891" to Value 2 in both my OPA891 and OPA2891 symbols and now my sims all work using my user defined locations.
Thanks to all who helped me figure this out. You spent precious time helping me and I deeply grateful.
Steve
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Show quoted text
On 2024-12-21 11:46, Andy I via groups.io wrote:
On Sat, Dec 21, 2024 at 10:56 AM, <info@...> wrote:
It is a pain to copy the model to every directory with an .asc in it and add the .lib directive to every simulation.? I really want to be able to add the symbol to the schematic and have LTspice find the proper model by itself.
....? Keep that model file in the same directory with your schematic - or move it to one of your User-defined Lib. Search Path
I don't know how you missed it.? Put the symbol in a folder in your User-defined Symbol Search Path, and put the model in a folder in your User-defined Library Search Path.? Those User-defined Lib. and Sym. Search Paths are in the LTspce Control Panel.? Symbols and models that are there in those user-defined locations, can be "seen" by LTspice schematics anywhere on your computer.? They are the user's equivalent of LTspice's own libraries.
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User-defined Lib. and Sym. Search Paths have been a part of LTspice for many versions and many years.? I think they were added in LTspice XVII, which dates them to eight years ago in 2016.
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This means that the "Andy" modified model should be able to live in my directory and the symbol should be able to call it, but I am not calling it correctly in the attributes of the symbol.
The model - whether it was "my" model or any other model - is totally, completely, 100% unrelated to where it lives!? If Windows finds the file, then LTspice finds the file and it does not care whose file it was.? If you make your own model file, great.? Go for it.? ?If you leave the model file unmodified from T.I., great.? Go for it.? No matter whether it is modified or the original unmodified file from T.I., it makes no difference to whether Windows and LTspice can find it.? The contents of the file and the location of the file are two completely independent things.
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Does renaming the Model Suffix from .lib to .sub matter?
I thought we made this clear already.? THE FILENAME DOES NOT MATTER, as long as you refer to it by its actual filename.? You can save or rename the model file with the filename FOOBAR.ARRGH if you want to.? As long as you call it by its actual filename, LTspice doesn't care whether the name ends in .lib or .sub or .mod or .txt or .doc or .xyzzy or even no extension.? All you need to do is make sure that you refer to it by its ACTUAL filename.? The filename extension is part of the filename. Don't let Microsoft Windows trick you into thinking that the filename's extension carries some sort of magic.? It doesn't.
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Andy
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eewiz
John Woodgate
John Waugaman