The decoupling capacitors on
PVDD, A, are very close to the device with the ground return close to the
ground pins. 8 100nF capacitors are recommended as Figure 8-2 shows. Another 4 1uF capacitors can be placed on the back of
the PCB.
Traces that carry large currents should incorporate multiple vias, B, to
reduce the series impedance of these traces.
A ground plane, C, on the same side as the device pins, helps reduce EMI
by providing a very-low loop impedance for the high-frequency switching current.
This plane should have many vias between the ground planes on other layers.
The ground connections for the capacitors in the LC filter, D, have a
direct path back to the device and also the ground return for each channel is
the shared. This direct path allows for improved common mode EMI rejection. This
should be on the same layer of the PCB as the TAS6754-Q1.
OUT_xP inductor, OUT_xP to OUT_xM capacitor, and the OUT_xM to GND capacitor,
E, need to have minimum loop size, starting from the device’s OUT pin
to GND pins. These are the switching related PCB traces. The loop size directly
influences the electric field coupling.
Heat-sink mounting screws, F, should be close to the device to keep the
loop short from the package to ground, providing a low impedance trace for the
high frequency noise coupled into the heatsink back to the PCB.