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ISO1212: Output failure mode of ISO1212

Gabriel Xu
Intellectual 2145 points
Part Number: ISO1212

Hi Team

Customer is using ISO1212 in their new project and have serverals questions:

  • What's the failure mode of ISO1212 in output side? (Output HIZ? or Output open?)
  • ISO1212 data rate is up to 4Mbps, for low speed digital input channel, could we add RC filter to limit the bandwidth? Where should I place the RC circuit?
  • What's the major purpose of the CIN in below diagram? 
  • Do we have internal pull-up or down for OUT pin?

  • 0
    TI__Expert 8030 points

    Hi Gabriel,

    Thanks for reaching out. Here are my answers to your questions:

    1. Like many other logic outputs, the output side of the ISO1212 does not have a defined failure mode. The output pins are standard CMOS outputs. If the absolute maximum conditions are exceeded, the output can fail randomly.

    2. Yes, you can use an RC filter to limit the bandwidth. However, this is not necessary, because an RC filter is already formed by RTHR and CIN. Therefore, you can adjust CIN achieve the desired bandwidth of your application.

    3. The major purpose of CIN is to filter noise and surges on the input pins. For CIN, we recommend using a 1 nF or greater capacitor to slow down transitions on the SENSE pin, and prevent overshoots beyond 60 V transitions.

    4. There are no internal pull-up or pull-down resistors connected to the OUT pins of this device. The state of the output pin is always defined by the state of the input and output enable pin. For example, when the input is open and the enable pin is high or open, the output will be low. When enable is low, the output will be high impedance. For more information about the different functional modes of this device, please refer to Section 8.4 of the device datasheet. 

    Please let me know if you have any additional questions.

    Regards,

    Kenneth