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TPS65214: Calculating Slew Rate

phytecBSC
Prodigy 180 points
Part Number: TPS65214

Tool/software:

Hello.

I just try to calculate the input slew rate for the PMIC. But I am kind of struggling to find everything. According to the datasheet you should be able to calculate it with this formulas:

The V_HEADROOM can be calculated with the formula in the figure. But I really can't find the value for VSYSPOR_Rising. I also searched in the NVM datasheet, but can't find anything.

Or is this not about calculating rather measuring?

And am I right, that I need to calculate it for every output, and then find the worst case in order to determine if my input slew rate is in spec?

Kind Regards

  • +1
    TI__Genius 9317 points

    Hello, 

    VSYSPOR_Rising is not explicitly stated in the datasheet, but this is typically 1.8 V - 2.275 V. I would use an average value of ~2.05 V here for calculations.

    I would run the calculation with your expected output voltage for each output rail in your use case and check that this is within spec.

    Does this help to answer your question? Let me know if more clarification is needed.

    Best Regards, 
    Sarah 

  • 0 in reply to Sarah Lao
    Prodigy 180 points

    Hello Sarah.

    Thanks for the info. But would be nice if you could add that value in future datasheet.

    Do you also have a time for t_NVM_LOAD? I would have thought this should be also in the NVM datasheet, giving the name.

  • +1 in reply to phytecBSC
    TI__Genius 9317 points

    Hello, 

    Yes, thank you for the feedback, I agree, we will look into adding these in the next revision of the datasheet.

    t_NVM_LOAD is 4.95 ms (max).
    This is the time that it takes the NVM to load to the device, so it isn't necessarily NVM-specific. 

    Best Regards, 
    Sarah

  • 0 in reply to Sarah Lao
    Prodigy 180 points

    Hi Sarah.

    Thanks a bunch, this should help to calculate it.