0 Members and 1 Guest are viewing this topic.

#### fc3000

• Regular Contributor
• Posts: 66
• Country:
« on: September 27, 2023, 10:55:28 am »
Hi all.
I am using  a INA139 in my project.
As i was studying the datasheet, cannot understand the chart below.
The output error is both negative and positive value!!
Regards.

This is the full datasheet: https://www.ti.com/lit/ds/symlink/ina169.pdf
Technology is Magic Made real.   (Elon Musk)

#### Psi

• Super Contributor
• Posts: 9967
• Country:
« Reply #1 on: September 27, 2023, 11:13:01 am »
Not sure I understand your question.

Error can be positive or negative.  Above the correct value or below the correct value.

In this case, as Vin gets lower the error becomes more negative.
Greek letter 'Psi' (not Pounds per Square Inch)

#### fc3000

• Regular Contributor
• Posts: 66
• Country:
« Reply #2 on: September 27, 2023, 12:34:37 pm »
Hi. Thank you for the reply.
So, are you saying that the error is a deviation from the perfect output?
Regards.
Technology is Magic Made real.   (Elon Musk)

#### DavidAlfa

• Super Contributor
• Posts: 5970
• Country:
« Reply #3 on: September 27, 2023, 01:37:41 pm »
Exactly.
If nominal output is i.e. 1V, that's the deviation over it, based on input voltage and working temperature.
« Last Edit: September 27, 2023, 01:39:59 pm by DavidAlfa »
Stm32 Soldering FW      Forum      Github      Donate

#### fc3000

• Regular Contributor
• Posts: 66
• Country:
« Reply #4 on: September 27, 2023, 02:22:51 pm »
OK got it now!

Regards
Technology is Magic Made real.   (Elon Musk)

#### Terry Bites

• Super Contributor
• Posts: 2415
• Country:
• Recovering Electrical Engineer
« Reply #5 on: September 27, 2023, 05:59:31 pm »
Vin=(Vin+ - Vin-) is the voltage across the shunt, Is*Rs. Vin is referenced to supply voltage and the voltage across the load.
All these factors and temperature will lead to error terms. Most sense amps are not all that precise because the market doesn't demand it it.
Battery charging, motor shunts etc...
There are exceptions of course.

Smf