inrush surge (use a pre-charge circuit or anti-spark connector e.g. XT90-S)
conductive metal or carbon dust/swarf - put your ODrive in an enclosure if using in a dirty environment
edit: by the looks of your U4 chip I’d say it’s most likely 1: inrush surge. Was there a spark when you connected it? Are you using a power supply or a battery, and at what voltage?
If you are using a 56V supply then you have to be very careful, as the absolute maximum voltage for the chip is 60V, and if it exceeds that even for a nanosecond, there will be an avalanche breakdown which causes the chip to explode. When that happens, a lot of current will be drawn from the PVDD pin in the corner of U4, which would explain why that is also charred.
The board was connected to a power supply which was 53 V. The spark happened when the software had just been uploaded to the board, the board was either changing hardware configurations or starting to calibrate (the beep didn’t happen). The board was also in a dust free environment, the second option is therefor not possible.
For me it is still a bit strange why this inrush current might have happened this time but didn’t happend the previous 60 or so times the board was used. Do you have any thoughts about this? Also because the power supply was allready on (and the board was charged), it is unclear for me how the inrush current could have happened.
@Auke you’re right, if the power supply was already on, then an inrush surge is not possible.
However 53V is pretty high. Is it possible that the drive went into regen and was unable to dump the stored energy? (did the motor move at all?)
Is it possible that your PSU had high ripple or a control wobble, and momentarily output 60V? (I normally set an overvoltage lock-out on my PSU at 55V just incase anything raises the bus voltage to dangerous levels)
Otherwise, especially if this was immediately after or during a software update, then it could be the ODrive itself at fault. one of the devs eg @Wetmelon might shed more light for you here
Given the circumstances you described, I can’t see any particular reason why this would happen. @Auke Can you please email firstname.lastname@example.org with your order number and a link to this thread, and we can send you a replacement.