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TINA/Spice: Unexpected results on TINA-TI for non-TI op amp

Aaron Needles
Intellectual 615 points
Other Parts Discussed in Thread: TINA-TI, OPA300

Tool/software: TINA-TI or Spice Models

I use TI parts in many of my designs, but for this case I am trying to determine why I am getting unexpected results for a non-TI part, the ADA4841.  I am concerned that I am setting up something wrong in TINA-TI, since this is my first time using an imported macro model.

I have imported the model and created the following circuit.

At 10kHz and higher, SIG2 (red) is no longer fully tracking SIG1.  The model seems to be basically working, but there seems to be a frequency limitation. The ADA4841 is copied directly from Analog Devices' website.

Where would I start looking to diagnose this issue?

Thanks,

      Aaron

  • 0
    TI__Mastermind 39210 points
    Hi Aaron,

    Thanks for using TI parts and TINA-TI. Since the model is essentially running in TINA-TI, there was no issue in the import process. I can not comment on the quality of the ADI model, but if you would like to get to the root cause of this issue, I would recommend replacing this with a TI IC model and seeing if the issue still persists. If you need recommendations on which TI IC to use, we can help get that for you.
  • 0 in reply to Nikhil Gupta (Product Folder Models)
    Intellectual 615 points

    I was able to replicate with the TI part OPA300, and I realized that the issue is the capacitance that the op amp is driving through the 10 ohm resistor. If I reduce this capacitance or increase the resistor, the feedback into the negative terminal is able to keep up.

    Thanks,

          Aaron