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BQ2980EVM-883: PTC Configured option

Austin Allen
Intellectual 2355 points
Part Number: BQ2980EVM-883

Hi team,

Is there a version of the -EVM (or of the device for that matter) that is configured for use with an external PTC as described in the datasheet?

Best regards,

Austin Allen

  • 0
    TI__Guru* 79523 points

    Hi Austin,

    No, and there is not a version of the device configured for this option (see the datasheet Device Comparison Table). We have done some analysis recently and I do not think there is a PTC on the market that would work with this option either based on the way it is specified.

    Regards,

    Matt

  • 0 in reply to Matt Sunna
    TI__Intellectual 2355 points

    Hi Matt,

    Interesting. In that case, any reason I can't just pick an external pull-up? For example, if I wanted the shutdown to trigger at, say 75C and I were using Vdd= 3.3V and a Rbias of 250k and the below thermistor, 

    Could this theoretically work? the only danger I see is the tolerance of Rbias, tolerance of Rptc, and shifting Vih levels. Is there a maximum Vih value?

    Best,

    Austin

  • 0 in reply to Austin Allen
    TI__Guru* 79523 points

    Hi Austin,

    This may be able to work, but the problem is that it will generate a constant current draw from the battery. For most of our battery ICs with temperature protection, the only enable the pull-up for a moment every 1-2 seconds. And like you said, the tolerances will impact the accuracy.

    Regards,

    Matt