INA220: R_shunt and filter check

Tommy Tzeng

Genius 5065 points

Part Number: INA220

Tool/software:

Hi Team,

we have a few question and want to learn from you,

1. do i have to add this R_filter?

2. is there minmum on resistance value of R_shunt? since resistor have power limitation, our load is 12v/ 4.1A, if there only 2 resistors in parallel, is chance of damage.

but use three 0.025ohm, the parallel equivalent impedance will change from 0.0125ohm to 0.0083ohm, can we do this?

1 month ago

0 Mallika Senthil 1 month ago

TI__Intellectual 1340 points

Hi Tommy,

Tommy Tzeng said:
this R_filter?

The input filtering is optional, please refer to section 8.4.1 of the INA220 datasheet for more detail.

Tommy Tzeng said:
minmum on resistance value of R_shunt

There is no minimum Rshunt value per say, but smaller the Rshunt, smaller the signal, so ensure your gain is set to amplify the signal effectively.

Tommy Tzeng said:
but use three 0.025ohm

Yes, you can use 3 Rshunt resistors in parallel, your schematic looks good as well.

Best,
Mallika Senthil

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INA220: R_shunt and filter check