Notes

1. The AP AUX-0025 low pass filter is necessary for class-D amplifier measurement with AP analyzer.

2. Two 22µH inductors are used in series with load resistor to emulate the small speaker for efficiency

measurement.

8

Application Notes

should be connected with the speaker before it's

powered on, otherwise it will be damaged easily.

2.

When the PAM8403 works without LC filters,

it's better to add a ferrite chip bead at the

outgoing line of speaker for suppressing the

possible electromagnetic interference.

3.

The recommended operating voltage is

5.5V. When the PAM8403 is powered with 4

battery cells, it should be noted that the voltage

of 4 new dry or alkaline batteries is over 6.0V,

higher than its operation voltage, which will

probably damage the device. Therefore, it's

recommended to use either 4 Ni-MH (Nickel

Metal Hydride) rechargeable batteries or 3 dry or

alkaline batteries.

4.

One should not make the input signal too

large. Large signal can cause the clipping of

output signal when increasing the volume. This

will damage the device b

.

5.

When testing the PAM8403 without LC filters

by using resistor instead of speaker as the output

load, the test results, e.g. THD or efficiency, will

be worse than those of using speaker as load.

ecause of big gain of the

PAM8403

Test Setup for Performance Testing

AP System One

Generator

PAM8403 Demo Board

+OUT

Input

Load

AP

Low Pass

Filter

AUX-0025

AP System One

Analyzer

GND

-OUT

VDD

Power Supply

PAM8403

Filterless 3W Class-D Stereo Audio Amplifier

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