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INA216: INA214A1 output error

Yusuke Mukuno
Expert 7395 points

Part Number: INA216

Hi expert,

My customer is using INA216A1(Gain=25) for monitoring battery charge current.

They have an issue of output error, it is bigger than device spec after power up

Power up : connect plug-in ACDC adaptor at time=0 in the following glaff.

X : time (Minutes) , Y : voltage (V)

Could you please let me know the reason of thie issue?

Thanks

Muk

  • 0
    Guru 140200 points

    Hi Muk,

    a schematic would be helpful.

    Are you violating the absolute maximum ratings during the power-on or are you overstressing the INA216 in any other way? This could heat up the die and the die would need some time to thermally equailze again.

    Kai

  • 0 in reply to kai klaas69
    TI__Mastermind 35220 points

    Hello Muk,

    Did you account for the VOS?  Max VOS is 100µV so the error at the output can be 2.5mV so like you said this is larger than the error you are getting.  Do you have anything at the inputs that would cause the IB to give a larger error?  Are you measuring the high side current?  What is your VCM?

  • 0 in reply to Javier Contreras4
    TI__Expert 7395 points

    Hi Javir,

    Regarding VOS,

    The second glaff is showing 8mV max. Also it is showing difference between input and output/25(gain).

    I think, it is too large from device specs.

    VCM = around 4.8V

    ACDC adapter = 5V

    ACDC adapter(5V) > High side current sensing (shunt : 1ohm, max 100mA> battery charger > li-ion battery (50mAh)

    I will send the schematics by the directly e-mail. (it cannot disclose on the web)

    Thanks

    Muk

  • 0 in reply to Yusuke Mukuno
    TI__Mastermind 35220 points

    Muk,

    I have shared my email with you.  Please send.

  • 0 in reply to Javier Contreras4
    TI__Mastermind 35220 points

    Hello Muk,

    I have a few questions.  I agree that the voltage looks worse than expected.  Even adding the extra error from IB (~ 22uA * 10Ω = 220uV) and PSRR/CMRR ( 90dB * (5V-4.2V)  ~  25µV).   Is the GND of the INA216A1 the same as the measured reference voltage of the MCU?  What is the capacitance on the output?  Is there an isolation resistor before the measurement node or capacitor?  Is the input noisy?  From the schematic I would assume not.