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Original question:

ISO7763-Q1: Power Dissipation

ISO7763-Q1: Terminal resistors

Saraswathy G
Prodigy 100 points
Part Number: ISO7763-Q1

Is it needed to provide external terminal or current limiting resistors for each channel of this IC ? The block diagram already shows internal resistors of close to 1k. If yes, how to select the value of the resistors?

  • 0
    TI__Mastermind 24885 points

    Hello Sraswathy,

    Are you referring to external resistors to define the inputs in an undefined state?

    If so, then external resistors are not needed and when the line is Hi-Z, the device will have internal resistors to ensure the inputs and outputs are in the default state.

    Or, are you referring to current limiting resistors that are needed in the event of a failure? In other words if there is a functional failure of the device, that the device is not further damaged so that isolation is maintain (even though functionality is not).

    In this case, current limiting resistors are needed in series with each I/O of the device to ensure that if there is a primary failure of the device that there is not further damage that compromises the isolation barrier. The current limiting resistors are needed to be set so that the current into the device does not exceed the current listed in the "Safety Limiting Values" table assuming there is a short in the device from the I/O to VCC or ground. 

    Hope this helps to clarify, otherwise let us know how we can help!

    Best,
    Michael