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BQ25629: Recommended unused pin termination for D+ D- and PMID

Luke Sakamoto
Intellectual 2135 points
Part Number: BQ25629
Other Parts Discussed in Thread: BQ25628

Tool/software:

Hi team,

I was not able to verify information about the unused pin. Can you check?

Thanks,

Luke

  • 0
    TI__Mastermind 31550 points

    Hi Luke, 

    Please see my comments below. 

    In regards to PMID this pin requires both a 10uF and 0.1uF capacitor placed near the IC. This is shown in the typical applications diagram of the datasheet. These capacitors are critical and required as PMID pin is the nearest node to input of the buck converter. 

    If unused D+ and D- pins can be let floating. Please be aware if these pins are left floating the result of input detection when adapter is plugged in will always be to set input current limit to 500mA for an unknown adapter. This limit can be overwritten via I2C communication to the charger if desired. Alternatively, if customer wishes to automatically set a higher current limit they can short D+ and D- pins together. This will result in input current limit setting of 1.5A. 

    Please let me know if you have any further questions. 

    Best Regards,

    Garrett

  • 0 in reply to Garrett Kreger
    TI__Intellectual 2135 points

    Hi Garrett,

    Thanks for the quick answer. It makes sense.

    The usecase here has an external MCU and it can adjust the current limit externally so its okay. Furthermore, since D+D- is not needed, BQ25628 is also being considered.

    Another question. Since PMID is not used, PMID_GD is also not being used. Looking at the discription of this pin, it seems like this can be left as float. What do you think?

    Thanks,

    Luke

  • 0 in reply to Luke Sakamoto
    TI__Mastermind 31550 points

    Hi Luke, 

    Luke Sakamoto said:
    Another question. Since PMID is not used, PMID_GD is also not being used. Looking at the discription of this pin, it seems like this can be left as float. What do you think?

    Yes PMID_GD pin can be left floating if not used. 

    Best Regards,

    Garrett