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INA310A: ina310 bandwith reduction

Christian Schmid
Prodigy 10 points
Part Number: INA310A


Hello,

I use a INA310A3 to measure and supervise a current, witch is a bit noisy.
How large can I make a capacitor parallel to R2 (50-100k) if I use R1=10k. (fig 7-4 in datasheet).
I could enlarge R1 to 22k if it helps.
Supply is 12V.
Are there other simple possibilities to reduce the bandwith of the circuit ?

Please support.

Sincerely

Christian

  • 0
    TI__Genius 17600 points

    Hello Christian, 

    Thank you for your post. 

    With a noisy input, you can filter the output like you are saying to address any unwanted transients. 

    I would recommend calculating the LPF cutoff frequency with R1 being 10kΩ. 

    Keep in mind, this is a large resistor so a 1nF capacitor already puts you at a 15.9kHz cutoff frequency. 

    Typically, I would recommend a cutoff frequency 10X the max frequency of your input. 

    I hope this helps, 

    Joe

  • 0
    Prodigy 10 points

    Hello Joe,

    Thank You for the answer.

    My main question is, is 10k enough isolation resistor, so I can use a 10nF capacitor ? (or greater ?)

    The datasheet says (page 5): OUTPUT max capazitive load, no isolation resistor 500pF.

    I need a low cutoff frequency because the hysteresis is small and not adjustable.

    Christian