Ground Dual MAX14870


I have to ask a question about this component (Dual MAX14870) which permits to control the PWM for two motors outputs. I succeeded to make work the card with two motors without trouble first.
When I disconnected the 3.3V from the Arduino (and all was again on: input source, arduino, …), a resistance on the card burned so the card is dead, and it is also the same for the Arduino which controlled the card. It seems when I disconnected all the power of the input source went through the Arduino.
I connected all the ground of the card (expected the GND next to the Vin for the input source) on the ground of the Arduino. Is it the good thing to do? Because for other component which does the same thing, it is precised that all the grounds on the card has to be on the same ground, and more precisely the ground of the input source of power.

Thank you in advance for your help. And sorry for my approximative english :wink:


I am sorry that your motor driver and Arduino are not working. Can you explain what you mean when you say “I disconnected the 3.3V from the Arduino”? Can you send pictures that clearly show your connections at the time the boards were damaged, as well as a close-up of the component side of the board? Can you also tell me more about your system? Was the blue AVIN = VM jumper connected? What voltage were you supplying to VIN? Which Arduino are you using?

Also, all of the grounds on that board are internally connected. In general, for electronics like these, it is appropriate that all devices in a system share a common ground. So, connecting the grounds together like you did was good and is not likely the reason your boards were damaged.