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ISO7763: Recommended operating conditions of VIH & VIL

Koshi Ninomiya
Expert 4680 points
Part Number: ISO7763

Dear Team,

My customer evaluates the ISO7763DBQR on their board, and when they measure the input vottage waveform, it is wider than the recommended operating conditions.

VCCI=3.3V

Recommended operating conditions:

Absolute maximum ratings:

Input voltage waveform on their board is almost the same as Figure 9-4. Eye Diagram.


When I see this Figure 9-4 Eye Diagram, VIH_max is arouond +4.0V and VIL_low is around -0.75V. those are wider than the absolute maximum rating of Voltage at INx of -0.5V_to_Vccx+0.5V.
If this input voltage waveform of -0.75V_to_+4.0V is applied to INx of ISO7763, will the ISO7763 be damaged?

Input voltage waveform normally has overshoot and undershoot, so it will not be within the recommended operation condition of 0V_to_VCC.
How should I consider the range of the input voltage waveform?
What input voltage level would damage the ISO7763?

I look forward to your reply.
Thank you.

Best Regards,

Koshi Ninomiya

  • 0
    TI__Genius 12245 points

    Hello,

    Thank you for your question!

    As shown in the picture below the absolute maximum rating for the input voltage is -0.5V to VCCX + 0.5V. Since you are using a VCC of 3.3V, the input voltage range should be limited to -0.5V to 3.8V to avoid damage to the device. Since -0.75V to 4V is outside of this absolute maximum range, it could damage the device.

    As shown in the highlighted parts of the picture below from the recommended operating conditions, the recommended input voltage range is 0 to VCC. We recommend that you use voltage in this range to have normal device operation.

    Regards,

    Aaditya Vittal

  • 0 in reply to Aaditya V.
    TI__Expert 4680 points

    Hi Aaditya-san,

    Please let me confirm the following point.
    The ISO7763 datasheet, page 33, section 9.2.3 Application Curves, Figure 9-4. Eye Diagram at 100 Mbps PRBS 216 – 1 Data, 3.3 V and 25°C, VIH_max is arouond +4.0V and VIL_low is around -0.75V. You mean that this Figure 9-4 voltage waveform would damage to the device, do not you?
    Thank you.

    Best Regards,

    Koshi Ninomiya

  • +1 in reply to Koshi Ninomiya
    TI__Genius 12245 points

    Hello Ninomiya-san, 

    Yes, such a voltage from figure 9-4 can damage the device over a period of time or could shorten the lifespan of the device.

    The waveform that is shown is an oscilloscope capture of the output from the device. The undershoot and overshoot are most likely caused by the cables, trace, or probes and are not generated by the device itself. As stated earlier, we recommend customers not applying anything above the absolute maximum ratings.

    Regards,

    Aaditya Vittal