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ISO1212: Rth resistor in ISO1212 schematic

Part Number: ISO1212

Hi everyone, I have a question, in the ISO1212 or ISO1211, the Rth resistor must strictly be a MELF resistor or may also be any <1/4 W resistor, for example, a 1206 smd resistor

  • Hi Isaac,

    Thank you for using E2E Forum and showing interest in ISO121x devices.

    The device ISO121x doesn't have any requirement on the type of resistor used for Rth and you can use anything that meets the power requirements of your application.
    Talking about the advantages of the MELF resistor, they have pulse handling capability making them suitable for current limiting during transients like Surge. These resistors also have higher reliability, tighter tolerance and better temperature co-efficient. Based on whether the digital inputs will be subjected to transients and the tolerance requirements of your application, you can decide to use MELF or a regular SMD resistor.

    Let me know if you have any other questions, thanks.

    Koteshwar Rao