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INA101: INA219 -conversion vs sample time

Robin Zwick
Prodigy 10 points

Part Number: INA101
Other Parts Discussed in Thread: INA219

Hello,

I am using the INA219 in a time critical application. I was wondering if you could tell me the device specific sample&hold time of the ADC (when operated with 12bit resolution). The complete conversion time in this case seems to be 532 μs.

When triggering the conversion via SIF, how long does it take the ADC to start sampling the actual shuntvoltage/busvoltage?

How long is the sampling time?

Will a change of the sampled voltage, after sample&hold of the ADC is done, affect the measurement? 

Thanks for your answers!

Best regards

Robin 

  • 0
    TI__Mastermind 36510 points

    Hi Robin,

    The ADC starts sampling at the end of a conversion instruction, if it is operated in one-shot conversion mode. In this case the end of the conversion instruction corresponds to the stop condition of the I2C command. If it is operated in continuous conversion mode, then the next conversion starts as soon as the previous one ends.

    The ADC is not a standard sample & hold circuit, see datasheet quote:

    As a result, the ADC averages the input signal throughout the conversion period. Therefore sampling time is not applicable and yes, if the input signal changes during the conversion period, the measurement will vary accordingly.

    Regards, Guang