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SN65HVD230: Multiple chip failed on a BLDC motor controller

Part Number: SN65HVD230


We are using the SN65HVD230DR as a CAN bus transceiver on a BLDC motor controller. We are facing multiple controller units with the SN65HVD230DR out of order. Most of them are externally fine but do not work anymore. One presents a hole near the CANH pin (number 7) :

Could you say if this could happen because of some overcurrent OR overvoltage event (ESD) ?

Here the schematics :

No terminal resistor on the PCB (but on the cable), only an ESD diode (24V) that is not extremely well rated (absolute voltage on CANH/L are about 25V according to datasheet). Besides the ESD diode is not very well placed (not directly near the connector and not on the path between the connector and the transceiver):

What are the main causes of such ic failure ? I know that the protection design is not perfect but are those chips that sensitive to ESD from human body ?

Do you have any suggestion on how to better protect the SN65HVD230DR ?

Best regards,

  • Hi Mathieu,

    Thanks for sharing this issue on E2E and including the images and layouts used in this case. 

    I agree that this damage is likely caused by ESD or overvoltage conditions on the CAN bus. These stresses on the bus can be common as the signals are connected externally and are therefore exposed to an electrically hazardous environment. For this purpose, the CAN pin of this IC have increased internal ESD protection (16kV for Human Body Model), but still may need additional external protection for larger or lower impedance transient sources. This is especially true for DC bus faults that may apply a voltage above the absolute maximum of the bus pins. 

    For external ESD protection, it is important to select components that can adequately protect the transceiver device. In this case, the clamping voltage for this transceiver should be under 25V to prevent a transient from exceeding this absolute maximum specification. The current selection of the 24V TVS diode may not clamp early enough in this case, as larger currents can increase this clamp voltage well above 25V. In this case, the 5V or 12V version of this TVS may be a better solution.

    For placement, you are correct that optimally the protection device would be near the connector. This allows the transient energy to be dissipated to GND quickly and the fault voltage will be less likely to reach the protected device's pin. With the current layout, the transient must travel through the connections to the device pin before it can be dissipated by the TVS diode. This will likely significantly decrease the protection offered by the diode.

    In summary, I would recommend selecting a TVS diode with a lower clamping voltage and changing the layout to include the protection device near the board connector, in between the connector and the protected device.

    Let me know if you have any more questions.

    Eric Schott

  • Hi Eric,

    Thank you very much for kindly answering to my post.

    I will fix the design following your recommendations.

    But something is still annoying me. Why did you manufacture such a sensitive transceiver ? Compared to other references I found, the SN65HVD230DR has relatively low absolute maximum voltage capability (25V). Does it have some reasons ?


  • Hi Mathieu,

    Good question. This is an older device that was designed with a focus no industrial applications. In many of these systems, there was minimal risk that the CAN bus would be exposed to voltages too far outside of the specified ranges of this device. With lower requirements for such systems, it was more desirable for customer to see the cost benefit of lower max voltage capabilities - which can take up a significant amount of die space. 

    Newer devices such as TCAN1042 with 70V bus fault protection were designed for applications which expect a much more hazardous electrical environment for the CAN bus. With newer technology available and changing requirements for a shifting industry we have tailored new devices to fit the needs of such systems. We are currently working on updating our 3.3V supplied CAN transceiver portfolio to include high bus fault protection options as well to make sure systems that require both of these feature have reliable devices that will fit their needs. 

    Eric Schott