TINA/Spice/OPA838: PSpice OrCAD Capture Model for OPA838

Ryan Eash

Part Number: OPA838
Other Parts Discussed in Thread: TINA-TI,

Tool/software: TINA-TI or Spice Models

Hello,

My colleague is trying to use the OPA838 with OrCAD Capture, but the TINA model does not seem to be compatible. It is comprised of many .subckt sections. How do we use this model in OrCAD or convert it to something usable?

Thanks!

over 6 years ago

0 Nikhil Gupta (Product Folder Models) over 6 years ago

TI__Mastermind 39210 points

Hi Ryan,

Can you share the error message that you are getting?

0 Ryan Eash over 6 years ago in reply to Nikhil Gupta (Product Folder Models)

Prodigy 70 points

The error message is irrelevant. It only loads this much of the model due to the ".ends" tag:

.subckt OPA838 VOUT VS- VIN+ VIN- PDBAR VS+
XI0 VS- VS+ VIN- VIN+ VOUT PDBAR VFA
.ends

There are MANY .subckt sections in the model file. PSpice can't load them all, because it sees the first ".ends" and stops. The model file as-is isn't compatible with PSpice, as far as I know.

Thanks,
Ryan

0 Ryan Eash over 6 years ago in reply to Ryan Eash

Prodigy 70 points

My boss actually tried running the model in spice in Altium, and that generated a bunch of simulation errors, so when we imported to Capture to try in PSpice there, we saw that it was only loading the model to the first ".ends".

0 Ryan Eash over 6 years ago in reply to Ryan Eash

Prodigy 70 points

The error just says that the "subcircuit is undefined". When you open the model for the part, it shows that it has only loaded up to the first ".ends", which is only a tiny portion of the model.

0 JC Zhu over 6 years ago in reply to Ryan Eash

TI__Mastermind 29035 points

Hi Ryan,

How did you "load" the model when you say "PSpice can't load them all"?

To use the file OPA838.LIB, you need to do 2 things:

Create a libary (an OLB file) so that you can place a symbol in your schematic. This is done by the cadence model editor. It reads the file OPA838.LIB and creates the pins for the the top-level subckt ONLY.
Include the model file OPA838.LIB so PSPICE can find the subckts needed for simulation.

See this example where I circled the two files:

Thanks,
JC

0 Ahana Ghosh over 6 years ago in reply to JC Zhu

TI__Intellectual 820 points

Hi Ryan,

Please find PSpice project created for OPA838 and attached herewith (zipped format, needs to be extracted properly before opening).

OPA838_PSpice_E2E.zip

Model runs fine without any complain/issue in PSpice, as checked/verified for an AC & transient test case, based on OPA838 TINA-TI Reference Design that exists on web.

The 2 test benches are there inside the project I have attached & can be run by activating & running the respective simulation profiles. (snapshot of project below)

0 Ryan Eash over 6 years ago in reply to Ahana Ghosh

Prodigy 70 points

Yes, we had created an OLB file and used the OP838 from it. But we did not have the OP838.lib in the "Model Libraries", so the OrCAD simulation was not able to grab the other subcircuits needed. So now it works in OrCAD. What is the equivalent of doing that in Altium? Since that is where we ultimately need to be.

Thanks,

Ryan

0 JC Zhu over 6 years ago in reply to Ryan Eash

TI__Mastermind 29035 points

Ryan,

Sorry, i don't have any experience with Altium. I guess you can follow this document?

www.altium.com/.../ap0142 linking a simulation model to a schematic component.pdf

Thanks,
JC

0 Ryan Eash over 6 years ago in reply to JC Zhu

Prodigy 70 points

Well we do that all the time....link models to Altium schematic components. But this TI model is not standard since it uses many subcircuits in one model file.

0 JC Zhu over 6 years ago in reply to Ryan Eash

TI__Mastermind 29035 points

Ryan,

If you think that's what causes the problem with Altium, feel free to move the first .ends to the end of the model file and try again. Berkely SPICE supports subckt definition within another subckt, which effectively changes its scope.

Thanks,
JC

Simulation, hardware & system design tools

Simulation, hardware & system design tools forum

TINA/Spice/OPA838: PSpice OrCAD Capture Model for OPA838