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INA228: I2C Secondary Device Address - connecting A0/A1 to SDA or SCL

Part Number: INA228
Other Parts Discussed in Thread: INA226

Hi -

On the INA228, when selecting a Secondary Device Address for I2C such that A0 or A1 is connected to SDA or SCL pin, should this be directly connected to the SDA/SCL pin or should it be attached through a  resistor?

Given that SDA and SCL are I2C bus pins and common to every other device on the I2C interface, I just want to make sure that there are no other drawbacks to selecting addresses that require the A0/A1 connection to SDA/SCL.

A follow-up question is whether using the A0/A1 connection to SDA/SCL adds to the capacitive load seen by the I2C bus because A0 or A1 are also theoretically connected to the bus in addition to the SDA/SCL pins?

Thanks,

Tom

  • Hello Tom,

    When using SDA or SCL for address pins, it is best to connect them without a resistor.  These are designed not to interfere with I2C communication, but if you are wanting more specific details then you can look at the IBIS model for the INA226 (we don't have an IBIS model for the INA228, but the model for the INA226 will be very similar. This can be found here:https://www.ti.com/lit/zip/sbom458).