Hello,
We have dozens of PCBs previously manufactured that use the LMD18200. However, we plan to use now the LMD18201. We are aware of the differences between both devices regarding the current sense feature. For the LMD18200 PCBs we layout and populated a 1206 size SMD resistor to sense current, although that feature it was never used at all. The current sense pin then goes to a microcontroller's A/D input pin, but as I said, it was not implemented in the microcontroller's firmware.
Now, for using the LMD18201 (again without using current sense) we need to join POWER GROUND and SIGNAL GROUND pins. We are wondering if we could still populate a 1206 size SMD zero ohms jumper resistor instead of our old (unused) current sense resistor to join POWER GROUND and SIGNAL GROUND. Besides the internal logic circuitry used to control the PWM switching, are there any other potentially moderate or high currents that could appear at SIGNAL GROUND pin that prohibits the use of a small size 1206 zero ohms resistor intended as the join path for both GROUND pins? The PCB track for the POWER GROUND is thicker enough to support the motor currents, but we are worried about the SIGNAL GROUND pin overheating a 1206 size zero ohms jumper resistor. In the datasheet appears a quiescent supply current, but we do not know if the SIGNAL GROUND pin also have other components increasing the current at that pin.
Thank you very much in advance for any information you may provide.
Regards.
