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INA226: Which ground to use?

Part Number: INA226

I've previously seen implementations of the INA226 where it uses the negative side of the load as a ground. 

The TI diagram, figure 30, in the datasheet seems to insinuate you can share ground with the processor.

Am I misunderstanding this diagram, or can you indeed do that?

  • Hello Marc,

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  • Hi Marc,

    I don't see how your question and figure 30 interrelate with each other. Can you show a schematic to make it clearer, please?

  • Hello Marc,

    I can assist you with you questions. To answer your question directly, the INA226 can indeed share its ground with the ground of the processor. It can also share the ground with the load. In fact, it is recommended that that the INA226, the load, and the microprocessor communicating with INA226 all have a shared/common ground. If one of the system's ground levels differ from another, even by millivolts, then accuracy and performance can be diminished. Now I will say that since INA226 is a digital output that the matching of the INA226 and host processor grounds are not as critical as if the INA226 was an analog voltage-output device. The headroom in the I2C voltage logic levels allows for a little variation, but overall the INA226 and host processor still need a common ground.

    I hope this what you were asking about. If not, please post back.

    Peter Iliya
    Current Sensing Applications.