PAM8406

Document number: DSxxxxx Rev. 1 - 0

9 of 14

www.diodes.com

March 2013

© Diodes Incorporated

PAM8406

A Product Line of

Diodes Incorporated

Application Information

Application Note

1. When the PAM8406 works in Class-D with LC filters, it should be connected with the speaker before it's powered on, otherwise it will be

damaged easily.

2. When the PAM8406 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 PAM8406 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 than its operation voltage, which will probably damage the device. Therefore, it's

recommended to use either four 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 because of big gain of the PAM8406.

Test Setup for Performance Testing

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.

Maximum Gain

As shown in block diagram (Page 2), the PAM8406 has two internal amplifier stages. The first stage's gain is externally configurable, while the

fixed at 2x.The output of amplifier 1 serves as the input to amplifier 2, thus the two amplifiers produce signals identical in magnitude, but different

in phase by 180°. Consequently, the differential gain for the IC is

Mode Selection

When mode pin high, it features Class-D; mode pin low, it’s class AB. Mode pin can’t be floating.

Mute Operation

enables the outputs. This pin may be used as a quick disable or enable of the outputs without a volume fade. Quiescent current is listed in the

Shutdown Operation

In order to reduce power consumption while not in use, the PAM8406 contains shutdown circuitry to turn off the amplifier's bias circuitry. This

shutdown feature turns the amplifier off when logic low is applied to the SHDN pin. By switching the SHDN pin connected to GND, the PAM8406