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ISOS141-SEP: unused pins

Joey Christ
Intellectual 2280 points
Part Number: ISOS141-SEP

In my application, I don't need to use some of the channels of the ISOS141-SEP.  For the unused channels, how should I connect the unused I/O pins (left open, pull-low, pull-high, etc)?

thanks!

  • 0
    TI__Expert 8965 points

    Hello, 

    Thank you for your question!

    For an application, leaving unused pin as floating could cause the device to be less immune to noise. In order to immune to noise, you can set the channel input to its respective default state.

    Since the ISO141-SEP (non-F version) has a default output of HIGH, a pull-high would have to be used (connect to VCC) to make the device more immune to noise.

    Please refer to this FAQ for more detail: e2e.ti.com/.../faq-can-unused-channel-pins-on-a-digital-isolator-be-left-floating

    Regards,

    Aaditya Vittal

  • 0 in reply to Aaditya Vittal
    Prodigy 10 points

    Hello,

    What's the impact of having pull-down (10kOhms) or (0Ohms) to Ground instead of having pull-up resistors for the ISO141-SEP (non-F version) for unused pins? The output is left open.

    Does this impact the behavior of the IC ? 

    Thank you,

  • 0 in reply to Jeremy Chambon
    TI__Expert 8965 points

    Hello, 

    Thank you for your question!

    I have answered your questions below:

    1. What's the impact of having pull-down (10kOhms) or (0Ohms) to Ground instead of having pull-up resistors for the ISO141-SEP (non-F version) for unused pins? The output is left open.
      1. The current consumption would be greater for the 0 Ohm pull-down compared to the 10kOhm pull-down.
    2. Does this impact the behavior of the IC ?
      1. Using a 10 kOhm or 0 Ohm pull-down resistor does not affect the behavior of the device.

    Regards,

    Aaditya Vittal