Diodes PAM8303D - Manual (Page 12)

PAM8303D
Document number: DSxxxxx Rev. 1 - 7
12 of 16
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November 2012
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PAM8303D
A Product Line of
Diodes Incorporated
Application Information
(cont.)
PCB Layout Guidelines
Grounding
It is recommended to use plain grounding or separate grounds. Do not use one line connecting power GND and analog GND. Noise currents in
the output power stage need to be returned to output noise ground and nowhere else. When these currents circulate elsewhere, they may get
into the power supply, or the signal ground, etc, even worse, they may form a loop and radiate noise. Any of these instances results in degraded
amplifier performance. The output noise ground that the logical returns for the output noise currents associated with Class-D switching must tie
to system ground at the power exclusively. Signal currents for the inputs, reference need to be returned to quite ground. This ground only ties to
the signal components and the GND pin. GND then ties to system ground.
Power Supply Line
As same to the ground, V
DD
and PV
DD
need to be separately connected to the system power supply. It is recommended that all the trace could
be routed as short and thick as possible. For the power line layout, just imagine water stream, any barricade placed in the trace (shown in Figure
2) could result in the bad performance of the amplifier.
Figure 2. Power Line
Components Placement
Decoupling capacitors-As previously described, the high-frequency 1µF decoupling capacitors should be placed as close to the power supply
terminals (V
DD
and PV
DD
) as possible. Large bulk power supply decoupling capacitors (10µF or greater) should be placed near the PAM8303D
on the PV
DD
terminal.
Input resistors and capacitors need to be placed very close to input pins.
Output filter - The ferrite EMI filter should be placed as close to the output terminals as possible for the best EMI performance, and the capacitors
used in the filters should be grounded to system ground.