INA260: Accuracy of the Current monitor chip

Fadi Safadi

Part Number: INA260
Other Parts Discussed in Thread: INA226,

Hello everyone,

i am designing an application related to power supplies and Battery management systems and i would like to measure the current through a shunt resistor.

i am choosing my Current Monitor Chip and now i summarized all my options to two : INA260 and INA226.

I prefer for sure a prefered high accurate messarument, the thing is am confused the INA260 is new more than the 226 and i checked realy precisly both datasheets.

the 226 has better gain error and better offset also better CMRR ( basically all 3 most important parameters are better here ) but the the 260 is new. Can someone tells me the difference between both? like what did it change in this one? which one would you recommend for me? i am not measuring high currents anyway.

Another questions is , is this because the 260 comes with a built in Shunt Resistor which make the accuracy in it lower than the 226 without the resistor?, how do you choose the shunt resistor for the 226 for example? with ohms law only right? my input voltage and the current am expecting to measure true?

over 6 years ago

0 Peter Iliya over 6 years ago

TI__Mastermind 26730 points

Hello Fadi,

Thanks for checking out the TI portfolio. I compared the INA260 and INA226 and double-checked with other team members. If you are going to compare these parts you need to note that the shunt resistance sensed by INA260 is 2 mOhm, not 4.5 mOhm. Once you do this, you will see that the INA260 has all of the same specifications as INA226, if not better. The shunt resistance sensed is explained in Section 8.3.1.

For example, the INA260 has 150uA/V CMRR maximum. Convert this into voltage terms by 150uA/V * 2 mOhms = 300nV/V --> 20*log(1V/300nV) = 130dB minimum. The INA226 has 126dB CMRR minimum.

If you do this for offset (10uV), offset drift (100nV/degC), and ADC shunt voltage LSB (2.5uV), you will see the INA226 and INA260 are the same.

The gain error specifications for the INA260 are broken up into different dynamic ranges of the input (-15A to 15A and -10A to -10A). The INA226's gain error spec reflects the full output dynamic range (approximately 0.1V to 4.9V). This error goes down as you consider the gain over a larger range and thus the gain errors are essentially the same with the INA226 having a slight edge.

The INA260's internal shunt does provide a benefit in the gain error vs. temperature specs. This is a reduction of error by 25ppm/degC.

Another thing to note about all of this is that if you choose the INA226, then you will need a shunt resistor. Yes, you choose this resistance based off of Ohm's law and the currents you expect. For INA226, you want the shunt voltage to remain within -81.9175mv and +81.9175mV. If you choose a shunt resistor with 1% tolerance, then without any calibration, your error among systems becomes 1%. This is something that you would not have to worry about with the INA260 and this is why the part is newer and costs more.

Post back if you have any more questions.

Best regards,

Peter Iliya

Current Sensing Applications

0 Fadi Safadi over 6 years ago in reply to Peter Iliya

Prodigy 100 points

Hello Peter,

thanks alot for your answer. I think i will for the INA260 for the temprature consideration you mentioned!. Is there a way later on to reduce the shunt resistor coming with the 260 or increase it?

Best regards,
Fadi

0 Peter Iliya over 6 years ago in reply to Fadi Safadi

TI__Mastermind 26730 points

Hey Fadi,

No problem. Unfortunately, the INA260 integrated shunt resistance is in a Kelvin sensing connection and is fixed at 2mOhm.

Post back to the forum for any of your questions.

Sincerely,
Peter Iliya
Current Sensing Applications

Amplifiers

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INA260: Accuracy of the Current monitor chip