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LMH6702: Noise model for LMH6702

Saad Qayyum
Prodigy 185 points
Part Number: LMH6702
Other Parts Discussed in Thread: TINA-TI

Hello everyone,

I am simulating LMH6702 opamp in one of my designs using ADS. I am trying to match the theoretically calculated noise with the simulated one but they seem to differ somehow.

I was wondering if the simulations models provided at the website contain the noise voltage and current sources specified in the datasheet or one has to add them themselves.

http://www.ti.com/product/LMH6702/toolssoftware#simulationmodels

Best Regards,

  • 0
    TI__Expert 7875 points
    Hi,

    The Model does include the noise sources. I checked the measurements using TINA-TI and did find that the voltage noise measures slightly higher than expected at 2.13 nV instead of 1.83 as mentioned in the datasheet. This is due to slight approximation errors in the model development.

    Regards,
    Jacob
  • 0 in reply to Jacob Freet
    Prodigy 185 points

    Hi Jacob,

    Thanks for the reply. Is it possible to edit the spice model file to change the voltage noise magnitude? If so, where?

    Saad

  • 0 in reply to Saad Qayyum
    TI__Expert 7875 points
    Hi Saad,

    I've moved this thread to our TINA model team for further support.

    Regards,
  • 0 in reply to Saad Qayyum
    TI__Mastermind 33170 points
    Saad,
    The problem may not really be with the model.
    I can take a look at your circuit if you are willing to attach your ADS workspace to this thread.
    That being said, in some of our newer Spice models it would be possible to edit the noise magnitude. Unfortunately this model is older and revising single model parameters is not practical.
    Please let me know if you have any more questions.
    Regards,
    John
  • 0 in reply to John Miller - Sensing
    Prodigy 185 points

    John,
    Thank for for the reply. I have adapted my calculations to use 2.13nV voltage noise (as mentioned by Jacob) instead of 1.83nV (as specified in the datasheet). Now the calculated results are close enough.

    Also, I had to set the simulation temperature to be the IEEE standard i.e. 290K instead of 298K. It suggests that the spot noise densities specified in the datasheet are at the standard temperature.

    Best Regards,
    Saad