PAM8403
Filterless 3W Class-D Stereo Audio Amplifier
Magnetic
How to Reduce EMI (Electro
Interference)
Under Voltage Lock-out (UVLO)
circuitry designed to
The PAM8403 incorporates
detect low supply voltage.
voltage drops to 2.0V or below
capacitor
power line
speakers
When the supply
, the PAM8403
device comes out of
A simple
solution is to put an additional
1000 F
coupling
are short
μ
at power supply terminal for
if the traces from amplifier to
(<20cm).
outputs are disabled, and the
this state and starts to normal
≥2.2V.
function when VDD
ferrite bead filter as
Most applications require a
shown in Figure 2
. The ferrite filter reduces EMI
of
. When selecting a
Short Circuit Protection (SCP)
around 1 MHz and higher
ferrite bead, choose one with high impedance
at
circuit protection
damage to the
circuitry on the outputs to prevent
The PAM8403 has short
high frequencies, and low impedance at low
frequencies.
or output-to-GND
ircuit is detected on
a r e d i s a b l e d
removed, the device
device when output-to-output
short occurs. When a short c
t h e o u t p u t s , t h e o u t p u t s
immediately. If the short was
activates again.
Ferrite Bead
OUT+
Over Temperature Protection
220pF
Ferrite Bead
prevents the
the internal die
There is a 15 degree
Thermal protection on the PAM8403
device from damage when
temperature exceeds 140°C.
tolerance on this trip point from
OUT-
device to device.
220pF
xceeds the thermal
Once the die temperature e
set point, the device outputs
not a latched fault. The thermal
are disabled. This is
fault is cleared
die is reduced by
will prevent motor
begins normal
boating sound well and the device
Figure 2: Ferrite Bead Filter to reduce EMI
once the temperature of the
30°C. This large hysteresis
external system
operation at this point without
intervention.
Power Analog Microelectronics,Inc
www.poweranalog.com
09/2008 Rev 1.3
10
PAM [ POWER ANALOG MICOELECTRONICS ]
