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Different results for FRA using LTpowerCAD and LTspice

Category: Software


I have a different results for LT8643S based step-down converter.

LTpowerCAD report closed loop bandwith 100kHz, LTspice 130kHz.
Which of them can be trusted?

See attachment, please.

Anyway... LTspice FRA settings is very poorly documented, I can not find any application notes or other sourses.

Only single basic and very short information available at

[edited by: Levandovsky at 10:43 AM (GMT -4) on 4 Apr 2023]

Top Replies

    •  Analog Employees 
    May 7, 2023 in reply to John Kevin +1 verified

    Hi ,

    Please be advised that the updated model for LT8643S is now available in the library. Please sync your library by going to Tool>Update components

    This result matches the result from LTpowerCAD…

Parents Reply
  • Hi  ,

    Thank you for providing these files, we will investigate the cause. We already have a few hints what might be missing. But to give you a conclusion, it is likely that the LTspice model is missing something and must be fixed so what I said earlier about who to trust still holds true which is LTpowerCAD.

    A fix on the LTspice model of LT8643S is coming out soon. We will let you know once it becomes available.

    We appreciate your help in ensuring the highest quality of our LTspice models.