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LM25116: Undefined ranges for parameters

Paul11
Prodigy 230 points
Part Number: LM25116

The LM25116 datasheet lists only the nominal values for the current sense amplifier gain of 10, ramp generator transconductance of 5uA/V, and error amplifier unity gain bandwidth product of 3MHz. Is there any other information on how wide these parameters can range between?

  • 0
    TI__Expert 6245 points
    Hello Paul,

    I am referring this request to our LM25116 expert, Tim
  • 0
    TI__Guru 74032 points

    Hi Paul,

    That's all that we provide in the datasheet. I suspect the CS gain is very accurate. I will investigate further.

    Regards,

    Tim

  • 0 in reply to Timothy Hegarty
    TI__Guru 74032 points
    Hi Paul,

    The ramp generator GM limits are found indirectly from the Ramp Current 1 and Ramp Current 2 tests provided in the datasheet EC table.

    Ideally: IRAMP = GM(VIN - VOUT) + 25uA.

    More accurately, Ramp current 1 = GM*(VIN - VOUT) + RAMP current 2, where RAMP current 1 and 2 are provided in the EC table.
    => GM = (RAMP current 1 – RAMP current 2)/(60V - 10V) = 5.14uA/V nominal.

    The ramp currents are somewhat correlated (not obvious from datasheet), so taking min and max values for currents provides some guidance for GM, for example: (335uA -35uA)/(60V - 10V) = 6uA max. and (235uA -21uA)/(60V - 10V) = 4.28uA min.

    Regards,
    Tim