PAM8003

Document number: DS36421 Rev. 2 - 2

8 of 12

www.diodes.com

May 2017

© Diodes Incorporated

PAM8003

Application Information

1. When the PAM8803 works with LC filters, it should be

connected with the speaker before it’s powered on, otherwise it will risk being damaged

easily.

2. When the PAM8003

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 PAM8003 is powered with four battery cells, it should be noted that the voltage of four

new dry or alkaline batteries is over 6.0V, higher that its operation voltage, which will probably damage the device. Therefore, its

recommended to use either four Ni-MH (Nickel Metal Hydride) rechargeable batteries or three 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 because of big gain of the PAM8004.

5. When testing the PAM8803 without LC filters by using resistor instead of speakers as the output load, the test results, e.g. THD or efficiency,

will be worse than those of using speaker as load.

Test Setup for Performance Testing

Notes:

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

5

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

Power Supply Decoupling

The PAM8003 is a high-performance CMOS audio amplifier that requires adequate power supply decoupling to ensure the output THD and

PSRR as low as possible. Power supply decoupling affects low frequency response. Optimum decoupling is achieved by using two capacitors of

different types of noise on the power supply leads. For higher frequency transients, spikes, or digital hash on the line, a good low equivalent-

lower-frequency noise signals, a large capacitor of 20µF (ceramic) or greater is recommended, placing it near the audio power amplifier.

Large input capacitors are both expensive and space hungry for portable designs. Clearly, a certain sized capacitor is needed to couple in low

frequencies without severe attenuation. But in many cases the speakers used in portable systems, whether internal or external, have little ability

to reproduce signals below 100Hz to 150Hz. Thus, using a large input capacitor may not increase actual system performance. In this case, input

capacitor (CI) and input resistance (RI) of the amplifier form a high-pass filter with the corner frequency determined by equation below.

feedback and is apt to create pops upon device enable. Thus, by minimizing the capacitor size based on necessary low frequency response,

turn-on pops can be minimized.

C

R

2

1

f

I

I

C

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