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BQ2980: recommended PTC value

eyall abir
Prodigy 40 points
Part Number: BQ2980

Hello,

What is the recommended PTC value? (i didnt see it in the datasheet)

Is there any calculation formula in order to address specific temperature? please mark the relevant paragraph in the datasheet.

Thank you

  • 0
    TI__Genius 11315 points

    Hey Eyall,

    We do not have a recommended PTC value. The formula you are asking for would the voltage divider formula. The high level input for the CTR pin is between 0.4V and 1V, and the value of RPULL_UP is either 1.5, 5, or 8 mOhm. The value of RPULL_UP is factory configured. There is also a table that shows effective pull up resistance at CTR across VDD (Figure 7-5) that can help you choose a proper PTC value for your application.

    Keep in mind that the logic high threshold for CTR varies with VDD, so a PTC might not be a practical application.

    Thanks,
    Caleb

  • 0 in reply to Caleb Perez
    Prodigy 40 points

    Hello Caleb,

    Rpull_up can be 3 differnet values which is factory configured, each can result different PTC, so there are 3 possible different voltage dividers, is it right?

  • 0 in reply to eyall abir
    TI__Genius 11315 points

    Hey Eyall,

    That's correct.

    Keep in mind that there are currently no part numbers in production that have Rpull_up enabled. You'd have to speak with our sales team in regards to ordering you a custom part. If you are able to get a custom part, you can pick the value of Rpull_up.

    Thanks,
    Caleb