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INPUT IMPEDANCE OF ISO122U

Jong han Lee
Prodigy 20 points
Other Parts Discussed in Thread: ISO122

I'd like to know the INPUT IMPEDANCE of ISO122U, Precision Isolation Amplifier. There is a '8.2. functional block diagram' at page 8. Looking at Vin, I'd really like to know input impedance of inner OPAMP, A1. Not 200k of series resister.

  • 0
    TI__Genius 9975 points

    Hello Jong han Lee,

    We do not have any characterization data on the input impedance of that node. Please note that it is not accessible and cannot be measured from the pins of the IC. In general, the input impedance of A1 is much larger than 200 kohm but we cannot provide any specific number as such impedance cannot be characterized.

    Could you help me understand how the input impedance of A1 plays a role in your application? Maybe I can provide some additional thoughts to help you in your circuit design.

    Best regards,

    Jose

  • 0 in reply to Jose Duenas
    Prodigy 20 points

    As Analog input, Our client required Input impedance should be at least 10MOhm.

    if not so, we should consider suitable voltage range for lower impedance than 10M.

  • 0 in reply to Jong han Lee
    TI__Genius 9975 points

    Hello Jong han Lee,

    The input voltage range of the ISO122 is +/-10 V (for a VS2 supply of +/-15V).

    Best regards,

    Jose