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jwalters1955
France
2 Posts |
 Posted - 30 Aug 2023 : 16:26:46
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I've a created number of components which include a TL072, a 2N2222 and a 2N5547 dual JFET and included them into a design.
When I try to run a simulation using LTSpice, the two transistors don't appear in the Spice netlist '.cir' file but the Op-Amp does. If I [Output] <Netlist> they are there, all connected up correctly.
The SpiceDevice and SpiceModel parameters are set up in the component editor.
If I replace the Dual JFET with two 'N-Channel JFET' devices from the SPICE.cml library (which appears as a 2N3819), the SpiceDevice and SpiceModel are already set and the transistors show up in the '.cir' file. If, however, I save that device to my own library (under another name but retaining J2N3819 as the SpiceDevice parameter), add a package and another gate to form a dual device it disappears again when I add it to the circuit. Other than the library component being defined with a 'SPICE' package and mine with a TO71, I cannot see ANY difference between the way the components from the SPICE.cml library and my components are defined.
I have included the spice models for the two transistors explicitly in the [Extra SPICE Data] tab using .MODEL directives which do appear in the SPICE Netlist '.cir' file as expected. Other than reporting some nets with only one connection (because the transistors are missing from the '.cir' file), LTSpice runs without complaint.
I've also tried using 'J' and 'NJF' as the SpiceDevice parameter for the JFET but to no avail.
Removing the SpiceDevice and SpiceModel parameters from the 2N2222 and renaming it 2N2222A allows it to appear in the '.cir' file and that section of the circuit works so I assume that LTSpice is picking the model up from its own libraries.
Can someone please explain to me what's going on? |
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ianafh
United Kingdom
25 Posts |
Posted - 01 Sep 2023 : 08:45:44
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Personally, I'd use the schematic editor in LTSpice for simulation. It's integrated and works perfectly well.
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jwalters1955
France
2 Posts |
Posted - 01 Sep 2023 : 10:44:49
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Thanks ianafh for coming back. I've done that for several projects but then I have to re-daft the schematic into EasyPC to produce the design and generate the PCB. Life would be so much easier (and safer) to be able to only design it once. On one previous project I missed a vital resistor from the EPC schematic which caused all manner of grief when trying to debug the hardware. Unfortunately, there's no mechanism for transferring the schematic from LTSpice to EPC.
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edrees
United Kingdom
766 Posts |
Posted - 01 Sep 2023 : 11:05:56
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John,
I recently had issues with NPN and PNP SOT23 transistors as the LTSpice (schematic) library entries were being selected in preference to my bespoke library.
Some of the components in the EasyPC LTSpice library seem to "map out" differently to the "industry standard" pin out.
My solution, -delete all EasyPC LTSpice libraries, -problem solved!
Most of the time, I would only need to simulate a small sub-section of the overall schematic in LTSpice anyway, so the greater part of the schematic would still have to be drawn one way or the other anyway. |
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Components not appearing in LTSpice '.cir' file.