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PGA281: LTSpice simulation error

Danilo A.
Mastermind 24715 points
Part Number: PGA281
Other Parts Discussed in Thread: TINA-TI

Hi Team,

Our customer is simulating PGA281 with LTSpice and noticed that the simulation shows some error in the signals. In the upper part of the screenshot is the input signal and in the lower one is the output. The gain is 1/8 so he is expecting a signal of ±0.5V at the output. Is this simulation error due to the encrypted Spice model of PGA281?

Regards,

Danilo

  • 0
    Guru 140200 points

    Hi Danilo,

    works in TINA-TI:

    danilo_pga281.TSC

    Kai

  • 0 in reply to kai klaas69
    TI__Mastermind 49465 points

    HI Danilo,

    The PGA281 model is unencrypted, therefore, I am not sure if this is due to another compatibility issue between this particular model and LTSpice.   Unfortunately, I am unable to directly reproduce/support simulations on LTSpice tool since this is a simulator from a different vendor.  The PGA281 model was released on 2013 and has been tested/verified to work within TINA TI.  Kai has provided a PGA281 simulation file above.

    Thank you and Regards,

    Luis

  • 0
    TI__Guru* 93105 points

    Hi Danilo,

    I was involved in the development of the PGA281 simulation model. We tested it with different PSpice compliant simulators and found that it ran correctly and without incident in any one we tried. As Luis indicated we cannot assist with LT Spice simulation issues involving TI models because the simulator is the property of a TI competitor.

    I show below a simulation of the PGA281 model that I receive from TopSPICE, which is a for purchase simulator that I use. I ran DC and transient simulations and had no difficulty attaining convergence and correct results with TopSPICE. The transient response is shown below. Like Kai who applied TINA-TI Spice I had no problems running a simulation.

    All we can really do is suggest you contact the owner of LT Spice applications team. It seems reasonable that they should be able to assist your customer further.

    Regards, Thomas

    Precision Amplifiers Applications Engineering

  • 0 in reply to Thomas Kuehl
    Guru 140200 points

    Hi Thomas,

    it works for me in LTSpice Relaxed

    danilo_pga281.zip

    Kai

  • 0 in reply to kai klaas69
    TI__Mastermind 49465 points

    Kai,

    Thank you for your help!

    Kind Regards,

    Luis

  • 0 in reply to Luis Chioye
    TI__Mastermind 24715 points

    Hi Kai,

    Thank you very much for simulating the PGA281 in LTSpice and for sharing the simulation result.

    Regards,

    Danilo

  • 0 in reply to Danilo A.
    TI__Mastermind 24715 points

    Hi Kai,

    We have received this feedback from our customer,

    Thanks for the answer:
    Unfortunately I couldn't open it because I don't have your PGA281 model.

    Could you please send it to me? (.asy and the .lib file)

    What have you done to get the model into LTSpice?
    I opened the .lib file that I downloaded from the TI webside mark the .subckt line in the lib file and generate a model out of this.
    Did you do anything different?

    Regards,

    Danilo

  • 0 in reply to Danilo A.
    Guru 140200 points

    Hi Danilo,

    I downloaded the PSpice model of PGA281 from the products folder on the TI's website and copied the file "PGA281.LIB" into the folder "LTspiceIV/lib/sub".

    I then started LTSpice and opened a new schematic. I inserted the directive ".inlcude PGA281.LIB".

    I opened in LTSpice the "PGA281.LIB" file and marked the .subckt line in the lib file to generate a model out of this, just like you did. Then I imported the generated model like a normal component into my schematic (via the "AND gate" in the header), which I picked up from the folder [AutoGenerated]. I drawed the full schematic and run the simulation. After showing me an error, I deleted the ".include PGA281.LIB" directive again. Afterwards the simulation did run without any issues.

    I added the asc. file above after zipping, as TI doesn't allow me to post a asc. file directly.

    It's important to note that LTSpice must be started in the "Run as administrator" mode!! Just double clicking on the LTSpice icon on the desktop will not do the trick.

    Kai

  • 0 in reply to kai klaas69
    TI__Mastermind 49465 points

    Hi Kai,

    Thank you.

    Hi Danilo,

    Let us know if you require further assistance with the PGA281.

    Thank you and Regards,

    Luis

  • 0 in reply to Luis Chioye
    TI__Mastermind 24715 points

    Hi Kai,

    The procedure you have shared resolved the issue. Thank you very much for your help.

    Hi Luis,

    The PGA281 is now working on LTSpice. Thank you for your support!

    Regards,

    Danilo

  • 0 in reply to Danilo A.
    TI__Mastermind 49465 points

    Hi Danilo,

    That's good news.  Let us know if you require anything. Thanks to Kai / Thomas for providing the procedure...

    Best Regards,

    Luis

  • 0 in reply to Luis Chioye
    TI__Mastermind 24715 points

    Hi Thomas,

    Thank you for your feedback and suggestion.

    Regards,

    Danilo