The PCB layout is critical for good and reliable operations, especially for high driver currents. A compact and clean PCB layout is extremely important as the TMC2209 provides a high-power density. A 4-layer PCB is a must, as is the usage of thick, straight and short traces for MOSFET and sense resistor interconnections. Provide as many wires as possible to allow heat transfer from the TMC2209 to the ground plane. The datasheet provides some more hints. Designers may also refer to the TMC2209-EVAL evaluation board, TMC2209-BOB breakout board and TMC2209 SilentStepStick.