Tool/software:
Hello,
I would like to know INA3221 effective shunt voltage resolution including error factor of VOS, DNL, INL.
With considering VOS +/-80uV, the effective resolution of INA3221 would be 80uV ,corresponding to 12bit resolution. If a customer use 10m-ohm shunt resistance, the effective accuracy would be 8mA or larger.
Is my understanding correct ?
best regards,
Hello Imi-san,
The offset doesn't directly affect the measurement resolution, but rather the smallest current that can be measured without calibration. The resolution is highly affected by your conversion and averaging settings, per these figures:
If you are looking for a more system level of accuracy at different current levels, then I suggest you use our error calculator tool:
https://www.ti.com/tool/download/CS-AMPLIFIER-ERROR-TOOL
You can use this tool to put in your system parameters and estimate system error. Please note that not all possible error sources are considered in this tool, but it does clearly state which error sources it is using.
You are correct that with your shunt resistor, an offset of 80µV (40µV typical) would correspond to an offset of 8mA (or 4mA typical).
For your information, we do have some newer multi channel devices that you may be interested it, the INA4235 and INA4230 (both are 4 channel devices).
Regards,
Mitch
