I wish to know the equivalent circuit of an input pin.

Dear All,

We are developing the product which used ADM489A.

The A/B input impedance is described to be 12kohm in the data sheet.

however, It seems that there is no information more than them about the A/B input.

Please let me know an equivalent circuit which is in the data sheet of other suppliers.

*An attached file is the product of Texas Instruments.

As for it, description by a text is also useful for me.

Best Regards,

DMN

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  • 0
    •  Analog Employees 
    on Jun 24, 2014 11:04 AM over 6 years ago

    Hi DMN,

    The attached is a simplified schematic for the input structures for the ADM489A.

    There are ESD structures on the A and B input pins.

    The input voltage over the -7V to +12V common mode range is divided down by the resistor divider network to provide voltage levels acceptable for the comparator circuitry.

    The level shifter circuit combination of current source and resistor network is used as a level shift to ensure that a negative input voltage (-7V -->) is shifted up to a positive voltage for the comparator circuitry.

    Regards,

    Richard

    ADM489AInputStructures.pdf
Reply
  • 0
    •  Analog Employees 
    on Jun 24, 2014 11:04 AM over 6 years ago

    Hi DMN,

    The attached is a simplified schematic for the input structures for the ADM489A.

    There are ESD structures on the A and B input pins.

    The input voltage over the -7V to +12V common mode range is divided down by the resistor divider network to provide voltage levels acceptable for the comparator circuitry.

    The level shifter circuit combination of current source and resistor network is used as a level shift to ensure that a negative input voltage (-7V -->) is shifted up to a positive voltage for the comparator circuitry.

    Regards,

    Richard

    ADM489AInputStructures.pdf
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