PAM8603MDET View Datasheet(PDF) - Power Analog Micoelectronics
Part Name
Description
Manufacturer
PAM8603MDET
Power Analog Micoelectronics
PAM8603MDET Datasheet PDF : 14 Pages
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PAM8603M
3W Filterless Stereo Class-D Audio Amplifier with DC Volume Control
Over Temperature Protection
Thermal protection on the PAM8603M prevents
the device from damage when the internal die
temperature exceeds 135°C. There is a 15 degree
tolerance on this trip point from device to device.
Once the die temperature exceeds the thermal set
point, the device outputs are disabled. This is not
a latched fault. The thermal fault is cleared once
the temperature of the die is reduced by 30°C.
This large hysteresis will prevent motor boating
sound well. The device begins normal operation
at this point without external system interaction.
How to Reduce EMI (Electro Magnetic
Interference)
A simple solution is to put an additional capacitor
1000μF at power supply terminal for power line
coupling if the traces from amplifier to speakers
are short (<20cm).
Most applications require a ferrite bead filter as
shown at Figure 3. The ferrite filter reduces EMI of
around 1 MHz and higher. When selecting a ferrite
bead, choose one with high impedance at high
frequencies, and low impedance at low
frequencies (MH2012HM221-T).
OUT+
Ferrite Bead
200pF
OUT-
Ferrite Bead
200pF
PCB Layout Guidelines Grounding
At this stage it is paramount to notice the
necessity of separate grounds. Noise currents in
the output power stage need to be returned to
output noise ground and nowhere else. Were
these currents to circulate elsewhere, they may
get into the power supply, the signal ground, etc,
even worse, they may form a loop and radiate
noise. Any of these cases results in degraded
amplifier performance. The logical returns for the
output noise currents associated with Class-D
switching are the respective PGND pins for each
channel. The switch state diagram illustrates that
PGND is instrumental in nearly every switch
state. This is the perfect point to which the output
noise ground trace should return. Also note that
output noise ground is channel specific. A two-
channel amplifier has two seperate channels and
consequently must have two seperate output
noise ground traces. The layout of the PAM8603M
offers separate PGND connections for each
channel and in some cases each side of the
bridge. Output noise grounds must be tied to
system ground at the power exclusively. Signal
currents for the inputs, reference, etc need to be
returned to quite ground. This ground is only tied
to the signal components and the GND pin, and
GND then tied to system ground.
Figure 3: Ferrite Bead Filter to Reduce EMI
Power Analog Microelectronics,Inc
www.poweranalog.com
11
10/2008 Rev 1.0
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