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BQ25790: Least components configuration

Alexander Slepoy1
Prodigy 105 points
Part Number: BQ25790

I'm considering using the BQ25790, but I have very limited PCB space, so I'm trying to figure out which external components are truly required to make it work. These are my questions:

  1. BATP, BATN pins instructed to have serial 100ohm resistors. I'm not going to use remote sensing. Can I just connect locally BATP directly to BAT, and BATN directly to GND with no serial resistors? Are the any consequences I should be aware of?
  2. IBAT pin is described as "sensing output". Seems like the charger is not using it for any internal logic. Can I leave the pin floating?
  3. ILIM_HIZ - if I'm not using this function, can I just short ILIM_HIZ to VREG?
  4. SDRV - if not used the datasheet requires 0402 50V 1nF capacitor. Can it be a 0201 capacitor with same characteristics? What will happen if there will be no capacitor on that pin?
  5. What is purpose of the capacitance on the BAT pins (2x10uF)?
  • +1
    TI__Mastermind 33081 points

    Hello Alexander,

    Alexander Slepoy1 said:
    BATP, BATN pins instructed to have serial 100ohm resistors. I'm not going to use remote sensing. Can I just connect locally BATP directly to BAT, and BATN directly to GND with no serial resistors? Are the any consequences I should be aware of?

    Yes, this should work, there should not be any consequences.

    Alexander Slepoy1 said:
    IBAT pin is described as "sensing output". Seems like the charger is not using it for any internal logic. Can I leave the pin floating?

    I recommend tying this pin to GND.

    Alexander Slepoy1 said:
    ILIM_HIZ - if I'm not using this function, can I just short ILIM_HIZ to VREG?

    ILIM_HIZ can be pulled directly to REGN to set max I2C register value (3.3A).

    Alexander Slepoy1 said:
    SDRV - if not used the datasheet requires 0402 50V 1nF capacitor. Can it be a 0201 capacitor with same characteristics? What will happen if there will be no capacitor on that pin?

    I highly recommend using 0402, I don't have the data to confirm if 0201 will work.

    Alexander Slepoy1 said:
    What is purpose of the capacitance on the BAT pins (2x10uF)?

    They are bulk caps, they prevents the output of of a supply from dropping too low during periods where current is not available.

    Best Regards,

    Christian.