Diodes PAM8010 - Manual (Page 12)

PAM8010
Document number: DSxxxxx Rev. 1 - 0
12 of 17
www.diodes.com
November 2012
© Diodes Incorporated
PAM8010
A Product Line of
Diodes Incorporated
Application Information
Test Setup for Performance Testing (Class D)
1. When the PAM8010 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 PAM8010 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 absolute maximum rating of the PAM8010 operation voltage is 6.0V. When the PAM8010 is powered with four battery cells, it should be
noted that the voltage of four 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 four Ni-MH (Nickel Metal Hydride) rechargeable batteries or three 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 PAM8010 has big gain, it will make the device damaged.
5. When testing the PAM8010 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.
Notes: 1. The Audio Precision (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.
Power Limit Function
The maximum output power of Class D section is set by applying a DC voltage at PL pin add a resistor divider from AV
DD
(Pin 6) to ground to
set the voltage at the PL pin. An external reference may alos be used at V
REF
(Pin 7) if tighter tolerance is required. Also add a 1µF capacitor
from Pin 7 to ground (see the application circuit on Page 1).
Different from other company’s power limit, the power limit circuit of PAM8010 sets a limit on the output peak voltage, and the value is lower
than the half supply voltage (PV
DD
) makes the PAM8010 never clipping, it means THD+N always lower than 1% when power limit works.
Noise Reduction Function
The gain of PAM8010 will reduce 12dB when there is no audio at the input of the amplifier for 8s. The gain will recovered until the input signal is
above the noise threshold which is set at V
TH
(Pin 18) and the noise threshold is set by an external resistr from V
TH
to ground.
Mute Operation
The MUTE_D pin is an input for controlling the Class-D output state of the PAM8010. A logic low on this pin enables the outputs, and a logic
high on this pin disables 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 electronics characteristics table. The MUTE_D pin can be left floating due to the internal pull-down.
The MUTE_AB pin is an input for controlling the Class-AB output state of the PAM8010. A logic high on this pin enables the outputs, and a logic
low on this pin disables the outputs.
Shutdown Operation
In order to reduce power consumption while not in use, the PAM8010 contains shutdown circuitry to turn off the amplifier’s bias circuitry. The
amplifier is turned off when logic low is placed on the SHDN pin. By switching the SHDN pin connected to GND, the PAM8010 supply current
draw will be minimized in idle mode. The SHDN pin can be left floating due to the internal pull-up.
For the best power on/off pop performance, the amplifier should be placed in the Mute mode prior to turning on/off the power supply.