Diodes PAM8603M - Manual (Page 9)

PAM8603M
Document number: DSxxxxx Rev. 1 - 1
9 of 14
www.diodes.com
November 2012
© Diodes Incorporated
PAM8603M
A Product Line of
Diodes Incorporated
Application Information
1. When the PAM8603M works with LC filters, it should be connected with the speaker before it is powered on, otherwise it will be damaged
easily.
2. When the PAM8603M works without LC filters, it's better to add a ferrite chip bead at the outgoing line of speaker to suppress the possible
electromagnetic interference.
3. 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 PAM8603M has big gain, it will make the device damaged.
4. When testing the PAM8603M without LC filters by using resistor instead of speaker as the output load, the test results, e.g. 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 done by AP analyzer.
2. Two 22µH inductors are used in series with load resistor to emulate the small speaker for efficiency measurement.
Mute Operation
The MUTE pin is an input for controlling the output state of the PAM8603M. A logic low on this pin disables the outputs, and a logic high 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 electrical
characteristic table. The MUTE pin can be left floating due to the internal pull-up.
For better power-off pop performance, the amplifier should be placed in the mute mode prior to removing the power supply.
Shutdown Operation
In order to reduce power consumption while not in use, the PAM8603M 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 PAM8603M supply current
draw will be minimized in idle mode. The SHDN pin can be left floating due to the pull-up.
Power Supply Decoupling
The PAM8603M 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 that target different noise on the power supply leads. For higher frequency transients, spikes, or digital hash on the line, a good
low equivalent-series resistance (ESR) ceramic capacitor, typically 1.0µF, placed as close as possible to the device V
DD
terminal works best. For
filtering lower-frequency noise signals, a large capacitor of 10µF (ceramic) or greater placed near the audio power amplifier is recommended.