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Problem with AD8336 model in LTspice

I'm using LTspice to simulate a circuit, and could not get the published AD8336 model to work. I searched Google and EngineerZone, but it still won't work. I do not have a background in spice models, so this is difficult for me to debug. Hopefully it's something simple, I would really like to use this device.

  1. To debug this issue, I'm using AEi Systems' test circuit for the model (Figure 4.5 on p.6 of the PDF attached here: https://ez.analog.com/message/26195?commentID=26195#comment-27724)
  2. The published AD8336 model will make LTspice throw an error about unrecognized functions (nonzero and np). Other threads on Engineer Zone (AD8336 Simulation in PSPICE Issues, AD8336 with ADISimPE) include revised models, which do not have these errors.
  3. With the revised models, the pre-gain amp half works fine, but VOUT from the VGA does not have an output. It's not railed - here's just no signal.

Can someone please help me get to the bottom of this?

Thanks,
Dan

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  • Sorry for the delay, and thanks for correcting that. Not sure how I ended up with .op instead of .options. The debug circuit works with those options. Unfortunately, when I pair this IC with others I'm simulating, the sim will never finish. It could be this model, or the other models, or user error. Unfortunately I don't have time now to debug it further. Anyway, thanks for helping to get the model working in this reference circuit

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  • Sorry for the delay, and thanks for correcting that. Not sure how I ended up with .op instead of .options. The debug circuit works with those options. Unfortunately, when I pair this IC with others I'm simulating, the sim will never finish. It could be this model, or the other models, or user error. Unfortunately I don't have time now to debug it further. Anyway, thanks for helping to get the model working in this reference circuit

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