Q: What are the best PCB layout practices for motor drivers and H-bridges?
Answer
Motor driver PCB layout is critical for thermal performance and EMI. Use a dedicated power plane for motor supply (VM). Place gate resistors (10-100 Ohm) within 5 mm of the MOSFET gates – long gate traces cause ringing. Use Kelvin source sense (separate current sense path from power path) for accurate current measurement. Keep high-current loops (MOSFET-motor-MOSFET) as small as possible to reduce di/dt loop inductance. Add RC snubbers (10 Ohm + 10 nF) across the MOSFETs to suppress voltage transients. Place bulk capacitance (100-1000 uF electrolytic + 10 uF ceramic) within 10 mm of the motor driver supply pin.
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