Can you test these drivers also in a different environment? As a last resort I suspect that you killed all test candidates by some bug in your PCB (missing GND or Vcc, wrong chip orientation...) or 12V applied prior to 5V.
Can you test these drivers also in a different environment? As a last resort I suspect that you killed all test candidates by some bug in your PCB (missing GND or Vcc, wrong chip orientation...) or 12V applied prior to 5V.