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DDC118: DC Bias Voltage

Sai Loo
Expert 4370 points
Part Number: DDC118

Hi,

In DDC118 datasheet, parametric table, it mentioned that the DC Bias Voltage is +/-0.05mV typical.

The definition of the DC Bias voltage is "voltage produced by the DDC118 at its input which is applied to the sensor", which is the input of the integrator.

My customer would like to know, when will the negative bias voltage happen?

  • 0
    TI__Prodigy 640 points
    Hi Sai Loo,

    I'm looking into this and will give you an accurate response as soon as I get this information.

    Thanks,
    Simon
  • 0 in reply to Saimon
    TI__Prodigy 640 points
    Sai Loo,

    The input offset of the amplifier arising from vt mismatch/charge injection will have a random component. In the absence of any systematic offset, having positive and negative offsets at the input is equally probable.
    This is due to internal switch capacitors setting that input value. It is therefore possible to see this negative values in spite of having only positive rails. It does not depend on external conditions that could be controlled, but simply that the device operation can create that voltage at the input.

    Hope this clarifies your question.

    Best regards,
    Simon