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SN65LVCP22: SN65LVCP22:OPEN FAIL

user763643
Prodigy 20 points
Part Number: SN65LVCP22

Hello.
Let me ask you some questions about the SN65LVCP22.

1. Does SN65LVCP22 have a built-in FAIL SAFE function?
　Looking at the circuit principle diagram, it does not seem to have the FAIL SAFE function.

2. I think you will add pull-ups and pull-downs to the inputs when inserting an open fail. At that time, does the pulse duty specification deviate from the data sheet?
　If a general offset within 100 mV is added, will it not meet the specifications?

3. In order to avoid the effect of 2. , if an open fail is not added to the input circuit with only the terminating resistor, an undefined state may occur internally.

　I am trying to select with the SEL signal to the side that is always connected. Is there a problem?

Thank you for your cooperation.

  • 0
    TI__Mastermind 43795 points

    Hi,

    1. Correct, the input has some threshold hysteresis, but it does not have an open failsafe function.  The minimum input voltage thresholds are shown as +100mv or -100mv.

    2. Depending on the input edge rate there will be some duty cycle degradation due to the offset threshold level.

    3. Correct. If the input is just connected with the resistor termination and no signal is applied then the output is undefined.

    If the SEL input is used to always select an input with a valid signal, there should not be a problem.

    Regards,

    Lee

  • 0 in reply to Lee Sledjeski
    Prodigy 20 points

    Hi Lee,

    Thank you for your answer.

    I am clear on any questions.

    I would like to proceed with method 3.

    Thank you very much.

    Yamaguchi