PAM8606
6W Stereo Class-D Audio Power Amplifier with DC Volume Control
Application Information
Heat Dissipation in PCB Design
Consideration for EMI
Generally, class-D amplifiers are high efficiency
and need no heat sink. For high power ones that
has high dissipation power, the heat sink may also
not necessary if the PCB is carefully designed to
achieve good heat dissipation by the PCB itself.
Filters are not required if the traces from the
amplifier to the speakers are short (<20cm). But
most applications require a ferrite bead filter as
shown in below figure. The ferrite bead filter
reduces EMI of around 1MHz and higher to meet
t h e F C C a n d C E ' s r e q u i r e m e n t s . I t i s
recommended to use a ferrite bead with very low
impedances at low frequencies and high
impedance at high frequencies (above 1MHz).
Dual-Side PCB
To achieve good heat dissipation, the PCB’s
copper plate should be thicker than 0.035mm and
the copper plate on both sides of the PCB should
be utilized as heat sink.
Ferrite Bead
OUTP
OUT+
The thermal pad on the bottom of the device
should be soldered to the plate of the PCB, and
via holes, usually 9 to 16, should be drilled in the
PCB area under the device and deposited copper
on the vias should be thick enough so that the
heat can be dissipated to the other side of the
plate. There should be no insulation mask on the
other side of the copper plate. It is better to drill
more vias on the PCB around the device if
possible.
200pF
Ferrite Bead
OUTN
OUT-
200pF
The EMI characteristics are as follows after
employing the ferrite bead.
Vertical Polarization
4-layer PCB
If it is 4-layer PCB, the two middle layers of
grounding and power can be employed as heat
sink, isolating them into serval islands to avoid
short between ground and power.
Horizontal Polarization
Power Analog Microelectronics,Inc
www.poweranalog.com
08/2008 Rev 1.1
12
PAM [ POWER ANALOG MICOELECTRONICS ]
