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I have models (.suckt) that are working perfectly in LTspice, when I import them in Qspice they dont work

Does Qspice use a different syntax?

Most (SPICE) simulators use the same general syntax, but all or most simulators have features that are not supported in all the others.

Some features in LTspice are proprietary and hence not available in other simulators.

Examples of uniqueness include VDMOS models and anything that uses an A-device, like UniversalOpamps or logic gates. There may also be a few functions that are not portable. However, unless you disclose which models you are referring to, it's not possible to comment further.

If you're wanting to use QSPICE, perhaps you should ask in a QSPICE group. Perhaps it has an LTspice to QSPICE converter, I don't know.

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For example I have the following error:

No such subcircuit: PROP_DELAY

I have "PROP_DELAY " in the 1st line of the .subckt model

That's not very helpful unless you provide an example.

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Can I upload the .subckt file?

Of course. Go to Files > Temp and click on the New/Upload button.

It would also be helpful if you could also provide a schematic that (successfully) uses the .subckt, and any other files that are not provided with LTspice. Put them in a zip, and upload that.

Don't forget to send another message if/when you do that.

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Many thanks, I've just uploaded the .ZIP file to temp:

Example Buck Boost for upload to group.zip

Please let me know if all is good

It contains the .asc file and the UCC27282 model as a .subckt

UCC27282 symbol is missing. According to your schematic file, it is in your "AutoGenerated" folder. You should copy that to the schematic folder, and edit the symbol ModelFile attribute to remove the hard-coded path.

However I can see in your schematic that you have used "standard" LTspice VDMOS models. As I said previously, these are not portable.

I also don't see .subckt PROP_DELAY. Did you upload the wrong file?

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In the example I uploaded I used BSZ076N06NS3 N-ch MOSFET?

But in Qspice I used IRFR7446 mosfet which I generated the model for in Qspice that is all good, but I think the error is with regards to the UCC27282 model and not the mosfet!

Anyway the uploaded .zip file should work in LTspice, but Qspice is giving me an error:

Fatal error: No such subcircuit: COMPHYS_BASIC_GEN

"COMPHYS_BASIC_GEN" is the 4th line written in the model after ".SUBCKT" command line, could it be the format (sytntax) needs to be written differently?

The reason why I want to run the Qspice simulation to see it simulates faster than LTspice!?

Well, we can't run it because you have not uploaded the missing/changed files.

The syntax for COMPHYS_BASIC_GEN seems normal. Many TI models use a similar methodology - they are often made using the PSpice model tool, and they normally work OK in LTspice.

The only thing I wonder is whether the PARAMS: VDD=1 VSS=0 VTHRESH=0.5 syntax is accepted in QSPICE. But since I don't use QSPICE, I couldn't test it, anyway.

Perhaps you could try changing it from:
.SUBCKT COMPHYS_BASIC_GEN INP INM HYS OUT PARAMS: VDD=1 VSS=0 VTHRESH=0.5
..
..

..to:
.SUBCKT COMPHYS_BASIC_GEN INP INM HYS OUT
.PARAM VDD 1
.PARAM VSS 0
.PARAM VTHRESH 0.5
..
..

If that works, I guess it will then throw up similar errors in turn for all the other .subckts that use the same syntax - they will need the same fix.

If that does doesn't work, I give up. I suggest you ask for help from the QSPICE forum. Similar compatibility questions have been asked there before, right from day one. You can't reasonably expect much help for QSPICE from a group "dedicated to LTspice".

--
Regards,
Tony