Since the DRV8218 device has integrated power
MOSFETs capable of driving high current, careful attention must be paid to the layout design
and external component placement. Some design and layout guidelines are provided below. For
more information on layout recommendations, please see the application note Best Practices
for Board Layout of Motor Drivers.
- Bypass the VM and VCC pins to GND using low-ESR
ceramic bypass capacitors. A capacitance of 0.1uF and X5R and X7R types are recommended.
For best results, place these capacitors as close to the device as possible to minimize
the loop inductance.
- The VM power supply bulk capacitor can be of
ceramic or electrolytic type, and is also recommended to be placed as close as possible to
the device to minimize the loop inductance.
- VM, OUT1, OUT2, and GND carry the high current
from the power supply to the outputs and back to ground. Utilize thick metal routing or
custom polygon pours for these traces if feasible.
- Connect the device thermal pad to the PCB top
layer ground plane and internal ground plane (when available) through thermal vias to
maximize the PCB heat sinking.
- Maximize the copper plane area attached to the
thermal pad for heat sinking.
- See Application Note - Best Practices for Board Layout of
Motor Drivers for more information on thermal management, routing techniques,
capacitor placement, and grounding optimization for motor drivers.