SN65HVD232: SN65HVD232 die every time!

Hello,

Thank you for your inquiry.  I have a few follow up questions in order to better understand your updated application.

Thank you for the attached schematic.  Do you have any schematic material that includes an SN65HVD232 device?  

For what reason did you switch the central unit to an isolated CAN device?

Have you done any pin testing yourself on a failed device (checking for shorts between pins, checking current consumption from the supply and from the CAN bus, etc.)?  Any information that you could provide from these simple tests can help to track the root cause of the failure.  If more device testing is needed, then we can discuss options for further failure analysis.

Thank you,

Max Megee

Transceiver Applications

Thank you for the attached schematic.  Do you have any schematic material that includes an SN65HVD232 device? 

The same as in this thread 

For what reason did you switch the central unit to an isolated CAN device?

Isolated CAN is better for medical devices. Central unit was upgraded earlier to ADM3053brwz and it worked with drivers with SN65HVD232 onboard. Then all SN65HVD232 burned.

Have you done any pin testing yourself on a failed device (checking for shorts between pins, checking current consumption from the supply and from the CAN bus, etc.)?  Any information that you could provide from these simple tests can help to track the root cause of the failure.  If more device testing is needed, then we can discuss options for further failure analysis.

Chip 1: short circuit GND, Vcc, CANL

Chip 2: short circuit GND, Vcc

Chip 3: short circuit GND, Vcc

Chip 4: short circuit GND, Vcc

Used tester - FLUKE 15B+

Thank you for the feedback.  I was looking through the previous thread.  Are the transceivers still in close proximity to BLDC motor wires?  Could they still be vulnerable to current outbursts?  

Have any changes been made to the system architecture to protect against electrical over-stress (EOS) on the SN65HVD232 devices?  Given the consistent nature of the VCC shorts to ground across multiple devices, it seems plausible that an over-voltage event could have exceeded the Absolute Maximum ratings of the device and created these shorts.  

Best Regards,

Max

Are the transceivers still in close proximity to BLDC motor wires?  Could they still be vulnerable to current outbursts?

Device was not working, BLDC motors were released, there were no reasons for power fluctuations.

Have any changes been made to the system architecture to protect against electrical over-stress (EOS) on the SN65HVD232 devices?

No, ESD diodes were not installed. 10 Ohm resitors were installed in a rupture of CANL and CANH circuits. It protected SN65HVD232 and it worked properly for a long time of our tests. As only 10 Ohm resitors were removed - instant burn on 3rd power turning on (even without working BLDC!). I do not even mind, where an over-voltage event could come from. Probably, the reason is in big capacity on each of 4 driver (2000 uF). Now they turns on without slow-charge schematic (just relay commutation) and current outbursts happens.

Would you be able to capture an oscilloscope waveform of the CANH, CANL, and VCC pins during power-up for the SN65HVD232 device in your application. Gaining a look at these waveforms can be a helpful debug step toward root cause.

Can you explain where the 2mF capacitors are sitting in your system? I could not find them in the schematics that you sent.

Since the failure event occurs after you remove the 10-ohm series resistors, then the electrical over-stress may be occurring on the CAN Bus itself. To your knowledge, are there any risks of over-voltage or over-current stress during power-up on the CAN Bus?

Thanks,
Max

2mF capacitors are placed on power input Vcc (+36V) directly at each BLDC driver. So, total capacity on Vcc is 2x4=8mF.

I probably will save and post oscilloscope waveforms sooner.

Thank you for the capacitor feedback. Are you able to capture any waveform checks on CANH, CANL, and VCC during power-up?

Thanks,
Max