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Hello Team,
Could you please tell me how to calculate the monitoring accuracy using INA197 ? I have a few question about this.
[Q1]
INA197 offset voltage MAX is 3mV. As the gain is 50V/V, does this mean that input error would be 150mV ?
[Q2]
Could you please tell me how to calculate the monitoring accuracy for INA197 ?
I believe below are the error factor.
- Input offset voltage (MAX)
- Gain Error (MAX)
- Common Mode Rejection (MIN)
- Power Supply Rejection (MIN)
- Input Offset Current (MAX)
- Shunt Resistor Tolerance (MAX)
If there is an app note which describes this, could you share us the material ?
Best Regards,
Kawai
Hello Kawai,
1. Correct. The input offset voltage is 3mV outside of room temperature operation, and this means that the output offset would be 150mV for a gain of 50V/V. It is important to note that this 150mV is output offset, not input error.
2. If you look on page 17 of the INA197 datasheet, you will see a section which goes into detail of the effects of Vsense, Common Mode voltage, offset voltage, and gain error in a comprehensive manner. You will see that depending on the system conditions, different graphs will be referenced that will help you, such as Figure 6 which shows the effect of common mode voltage on output error.
Regards,
-Kareem Moulana
Hello Kawai,
Also the Electrical Characteristic table in the INA197 datasheet has a Max Total Output Error spec of about 2.2% for Vsense= 100 mV (only including Vos and Gain error). There are additional errors like shunt resistor tolerances that contribute to the total error. Please take a look at the below table from another datasheet for an error calculation example (Note that RVRR error is not applicable for this device).