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LMZ31530 resistor value range for setting soft start and ILIM

K. Sasaki14
Guru 10200 points

The setting resistor value is decided on datasheet Table 5 for soft start time and Table 6 for ILIM.
Must we set the just value of datasheet Table 5 and 6? Or can we set several range?
Please let me know the resistor value range if there is any range. Could you tell me the required resistor accuracy if the just value is needed?

Best Regards,
Kohei Sasaki

  • 0
    TI__Mastermind 28020 points
    For both the slow start time and ILIM, the values listed in Table 5 & 6 are the only values for setting the limits. These values cannot be set over a continuous range.
  • 0 in reply to J Arrigo
    Guru 10200 points

    Arrigo-san,

    Thank your for your reply.
    I understood the listed value in datasheet is only value for setting. So I would like to know used resistor accuracy.
    Although just resistor value is used, resistor has error. What is the allowed resistor error? 5% is OK? Or 1% is must?

    Best Regards,
    Kohei Sasaki

  • 0 in reply to K. Sasaki14
    TI__Mastermind 28020 points
    The resistor accuracy will affect the overall accuracy. The most accurate resistor is best. See note 2 on page 4 of the datasheet.
  • 0 in reply to J Arrigo
    Guru 10200 points

    Arrigo-san,

    I think the note 2 on page 4 of the datasheet is the description about Vout accuracy. So I think this is not related to SS and ILIM setting.
    We would like to know required resistor accuracy used for setting SS time and ILIM threshold.
    We must set just resistor value which is listed in datasheet. What level the resistor error is allowed? 1% resistor is required? 5% accuracy is OK?
    Please let me know the variation level if you say any accuracy resistor  is OK  however SS time and ILIM threshold variation becomes large.

    Best Regards,
    Kohei Sasaki

  • 0 in reply to K. Sasaki14
    TI__Mastermind 28020 points
    Sasaki-san,
    I'm sorry, I misunderstood. You are correct, for SS and ILIM a 5% accurate resistor is OK.