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THVD2410: THVD2410DR - EFT Failure

Uvaraj Gajendran
Prodigy 10 points

Part Number: THVD2410
Other Parts Discussed in Thread: STRIKE

Hello,

I am using two different alternate transceivers (THVD2410DR & ISL32432E) in my deisng for isolated RS485 communiation.

When applying 2 kV EFT pulses (both positive and negative) to the signal lines, we are experiencing communication failures. However, when using the alternate part ISL32432E, the test passes without any issues. Below is the circuit for your reference. E

image.png

  • 0
    TI__Mastermind 19452 points

    Hi Uvaraj,

    Thanks for reaching out on E2E! I have several questions for you:

    • Can you confirm if there were any setup differences between the transceivers? Or did you simply just swap the transceivers using the same board?
    • Can you clarify if the THVD2410 is damaged or just experiencing temporary communication loss while under an EFT strike?
    • Did you strike both transceivers multiple times during communication and with consistent results?
    • Can you provide any EFT setup information? R/C parameters?
    • What is the external ESD diode that is present on the schematic? Is this populated for both transceiver tests?

    THVD2410 is rated for 4kV of IEC 61000-4-4 EFT strikes. However, communication during an ESD strike (especially EFT) is hard to guarantee. RS-485 transceivers are designed to survive ESD strikes, but none guarantee 100% communication success. 

    Best,

    Ethan

  • 0 in reply to Ethan Sempsrott
    Prodigy 10 points

    Hello,

    Below are my comments for your queries. 

    • Can you confirm if there were any setup differences between the transceivers? Or did you simply just swap the transceivers using the same board?

    I swapped the transceiver on the same board and tested using the same setup. The test passed with the Renesas part but failed with the TI part. Additionally, the test was repeated on three different PCBAs, all showing the same result. For the TI part, even the 500V test failed.

    • Can you clarify if the THVD2410 is damaged or just experiencing temporary communication loss while under an EFT strike?

    There was no damage to the TI part after testing. It continues to function normally in the setup without any issues.

    • Did you strike both transceivers multiple times during communication and with consistent results?

    I tested this on three PCBAs, and the result was the same each time.

    • Can you provide any EFT setup information? R/C parameters?

    EFT is injecting using this clamp for the cables bunch mentioned in XN4.

    • What is the external ESD diode that is present on the schematic? Is this populated for both transceiver tests?

    MPN#NUP2105LT1G used in the design. It is a assembled part for testing both TI and Renesas transceivers. 

  • 0 in reply to Uvaraj Gajendran
    TI__Mastermind 19452 points

    Hi Uvaraj,

    I appreciate the detailed responses. 

    It looks like your setup is accurate. Our device is still performing as expected: it survives an EFT strike and recovers. Communication during an EFT strike is not guaranteed. 

    If you want to try one more thing, my only other recommendation would be to test without the external ESD diode when testing the THVD2410. I have heard of the external ESD diode conflicting with integrated ESD protection before. It may not be the case here, but worth trying since you likely wouldn't need the external diode with the THVD2410 anyway. 

    You are also welcome to send over a waveform of the RS-485 bus and the R pin of the THVD2410 during the EFT strike. I can review this in case anything else is going on. 

    Best,

    Ethan