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INA220: INA220 Slave Address Configuration Problem of A0 and A1 Connections

Wayne Chen (ex FAE)
Guru 15950 points
Part Number: INA220

Hi Sirs, 

According to the INA220 datasheet, we can connect the A1, A0 to the SDA or SCL directly to define the INA220 device to certain slave addresses.
Will it make slave address configuration problem if customers connect the A0, A1 to SDA and SCL through 10kohm resistors? 



Thank you and Best regards,

Wayne Chen
10/23/2019

  • 0
    TI__Mastermind 26660 points

    Hey Wayne,

    I am not sure connecting the A0 and A1 pins to the SDA and SCL rails with the 10kOhm resistors would be robust due to how the device detects its configuration. I will need to check with the design team and I will get back with you tomorrow.

    Best,

    Peter

  • 0 in reply to Peter Iliya
    TI__Mastermind 26660 points

    Hey Wayne,

    There should be no reason to connect A0 and A1 with 10kOhm resistors and this is not a recommended circuit. It is probably more OK to connect address pins to ground or supply (VS) with the 10kOhm resistors, but problem can occur when connecting them to the SDA and SCL lines. The device needs to see the address pin = SDA or SCL for every positive edge during beginning of communication protocol in order to determine if it's slave address is being written to. When you add the 10kOhm resistors in between address pins and communication pins this will create an RC delay and because of this the device might not catch a positive edge, thus giving it a different slave address. This problem will assuredly become worse over temperature and communication speed.

    Hope this helps.

    Sincerely,

    Peter Iliya

  • 0 in reply to Peter Iliya
    Guru 15950 points

    Thank you for your confirmation, Peter...Wayne Chen