It is necessary to follow recommended PCB guidelines for EMC success. Proper PCB floor planning, component selection, component placement, and routing are all essential to counter EMI. Emissions are exacerbated by improper layout, components, and output trace length causing antenna effect. Practical PCB design guidelines for achieving EMC include:

• Place the high-frequency decoupling capacitors as close to the power pin and ground pin of the device as possible to reduce the parasitic inductance of the trace. To ensure low AC impedance over a wide frequency range for noise reduction, use good quality, low-ESR, 1-nF ceramic capacitors. For mid-frequency noise due to PWM transients, use another good quality 0.1 µF ceramic capacitor placed as close as possible to the PVDD leads.
• Use a continuous ground plane and avoid voltage offset on the ground planes whenever possible.
• Low impedance routing back to source (return signal).
• Power planes should be away from the edges of the PCB.
• Proper filtering of the PCB connectors.
• Place EMC snubbers and ferrite bead filters as close as possible to the IC. Minimize unfiltered loops and trace length as well as stray inductance.
• Keep amplifier output traces to the speaker as short as possible. PCB traces and the speaker wire are the largest sources of emission.