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INA333: Internal offset correction

Zoey Wu
Expert 4120 points
Part Number: INA333
Other Parts Discussed in Thread: INA350

hi team,

my customer want to use INA333 to amplify the 0-20mV voltage  and their application is the same as below.

they are afraid that when in mass production, their will be some voltage ripples about 5mV on pin 2 and pin3. they want to know if the internal offset correction can dismiss the ripple and do u have any other advice to avoid this except the datasheet shows? thanks! 

  • 0
    Guru 265600 points

    What kind of ripple? If VDIFF does not change, then you have common-mode noise that will be filtered out; see the CMR specification in section 6.5. (This has nothing to do with the internal offset correction.)

  • 0
    TI__Mastermind 18577 points

    Zoey,

    1. If the noise (ripple) is a common common mode signal, it can be rejected by CMRR of the INA333.  The INA333 has excellent CMRR.
    2. If the noise is differential, it will be amplified by INA333 (or any other INA).
    3. The offset correction (chopping) will not correct for external errors.  It only corrects internal offset.  This is why the INA333 has an MAX offset of ±25uV ±75uV/G.  The INA350 has an offset of 1.3mV MAX.  The offset drift is similarly improved on the INA333.
    4. For input filtering see page 53 of https://www.ti.com/seclit/eb/slyw038c/slyw038c.pdf .  Depending on the frequency of the noise signal you can use this kind of filter.

    Let us know if you have other questions.

    Art