Pam8001, Application information – Diodes PAM8001 User Manual
Page 10
PAM8001
Document number: DSxxxxx Rev. 1 - 0
10 of 17
February 2013
© Diodes Incorporated
PAM8001
A Product Line of
Diodes Incorporated
Application Information
1. When the PAM8001 works with LC filters, it should be connected with the speaker before it's powered on, otherwise it will be damaged
easily.
2. When the PAM8001 works without LC filters, it's better to add a ferrite chip bead at the outgoing line of speaker for suppressing the possible
electro magnetic interference.
3. The absolute maximum rating of the PAM8001 operation voltage is 6.0V. When the PAM8001 is powered with 4 battery cells, it should be
noted that the voltage of 4 new dry or alkaline batteries is over 6V, higher than its maximum operation voltage, which probably make the
device damaged. Therefore, it's recommended to use either 4 Ni-MH (Nickel Metal Hydride) rechargeable batteries or 3 dry or alkaline
batteries.
4. The input signal should not be too high, if too high, it will cause the clipping of output signal when increasing the volume. Because the DC
volume control of the PAM8001 has big gain, it will make the device damaged.
5. When testing the PAM8001 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 using speaker as load.
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.
Description of Adjustable Power Limit with Anti-Saturation
Adjustable power limit provides AGC to the amplifier and limit the Maximum Output Power.
The behavior of power limit function showing as below.
The power limit control detect output signal amplitude continuously, when the peak output is excised limit threshold (setting by external
resistor).Control system will decrease the one step gain(typical -0.5dB). Then attack time is reset for next gain decrease. The control system
will decrease the gain step by step until the peak output signal equal to the threshold level. After these, when the input signal's amplitude
decreased or DC volume control reduced the amplifier's gain or happened together, the control system will calculate the ideal output level.
When that level lower then limit threshold , the will start to recovery to the original gain (which is setting by DC volume control).The first release
step is no delay, reset with release time per step.