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I2C communication on BQ24168

WhiteHorse
Genius 4430 points
Other Parts Discussed in Thread: BQ24168

We have a customer that is not able to talk to the BQ24168 device reliably. Their clock speed is around 100 KHz.  What is the min and max voltage for I2C signal  1.8 to 4.4 ?  What is the recommended pull up resistor value and voltage  assuming there is only one fanout.?  Once in a while the bus hangs and they have to reset the device.  Please provide some recommendations on how to communicate reliabley with the BQ24168.

Regards,

John

  • 0
    TI__Genius 14317 points

    From the Data Sheet: "The I2C circuitry is powered from VBUS when a supply is connected. If the VBUS supply is not connected, the I2C circuitry is powered from the battery through BAT. The battery voltage must stay above 2.5V with no input connected in order to maintain proper operation."

    From what I see in the Data Sheet, the high level logic level is 1.3 V (Vih min) to 4.44 V (VBatreg) + 4.17%, which equals Vsys max. The Data Sheet recommends 10 k pull ups but you can use 2.2 k or so for faster edges.

    Please follow the Data Sheet I2C SCL/SDA timing recommendations and reference the NXP I2C specification for more details. The customer can also send a schematic and scope shots of SCL/SDA RD/WR cycles for review.