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Original question:

ISO122: Isolation amplifier

ISO122: Isolation amplifier

Vladimir Naumenkov
Expert 2970 points

Part Number: ISO122
Other Parts Discussed in Thread: ISO224, AMC1311

Please, answer another question

If I will use ISO122, can I use circuit in attach? Please, see attach.

TIA

Sincerely,

Vladimir Naumenkov

www.agat.by

Isolation amplifier_ISO122.docx

  • 0
    Guru 140200 points

    Hi Vladimir,

    I cannot answer this question because the datasheet does not have enough data. Maybe a TI's employee will be able to answer this question.

    When powering the chip with +/-15V, the input voltage range is +/-12.5V typically and +/-10V guaranteed. So, it seems that the input voltage should stay 2.5V (better 5V) away from the supply rails. This could mean that the ISO122 will provide an input voltage range of +/-2.5V typically, when powered with +/-5V. But it can also mean that due to manufacturing tolerances some ISO122 might not work at all even with a vanishing input signal.

    Remember that the ISO122 is from 1989. At this time OPAmps and isolation amplifiers like the OPA122 were usually powered with a bipolar supply voltage of +/-15V. The modern TI's AMC series, on the other hand, is free from these restrictions and can be powered with a single supply voltage of +5V.

    Kai

  • 0
    TI__Guru**** 182721 points
    Hi Vladimir,

    The ISO122 will work from +/-5V supplies and your 1-3V input should be fine. As Kai mentioned though, we'd rather see you move into something like the AMC1311 or ISO224. For the AMC1311, there is no access to a (-) input so you would need to level shift your signal. For the ISO224, perhaps you could gain up your input signal so that it was in the FS range of the amplifier.
  • 0 in reply to Tom Hendrick
    Expert 2970 points

    Dear Tom, thank you