PAM8010

Document number: DSxxxxx Rev. 1 - 0

13 of 17

www.diodes.com

November 2012

© Diodes Incorporated

PAM8010

A Product Line of

Diodes Incorporated

Application Information

Power Supply Decoupling

The PAM8010 is a high performance CMOS audio amplifier that requires adequate power supply decoupling to ensure the output THD and

PSRR are as low as possible. Power supply decoupling affects low frequency on the power supply leads for higher frey response. Optimum

decoupling is achieved by using two capacitors of different types that target different types of noise frequency transients, spike, or digital hash

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.

Large input capaciitors are both expensive and spce hungry for portable designs. Clearly, a certain sized capacitor is needed to capacitor is

needed to couple in low frequencies wothout 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

determined equation below,

C

R

2

1

f

I

I

C





In addition to system cost and size, click and pop perfomance is affected by the size of the input coupling capacitor, CI. A larger inout coupling

capacitor requires more charge to reach its quiescent DC voltage (nominally ½ VDD). This charge comes from the internall circuit via the

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

turn-on pops can be minimized.

supply caused by coupling into the output drive signal.

Over Temperature Protection

Thermal protection on the PAM8010 prevents the device from damage when the internal die temperature exceeds +150°C. There is a 15

degree tolerance on this point from device to device. Once the die temperature exceeds the thermal set point, the device outputs are disabled.

This is not a latched fault. The thermal fault is cleared once the temperature of the die is reduced by +40°C. This large hysteresis will prevent

motor boating sound well. The device begins normal operation at this point without external system interaction. Before thermal shutdown, gain

of the PAM8010 will drop -3dB when the chip temperature reaches +120°C.

How to Reduce EMI (Electro Magnetic Interference)

A simple solution is to put an additional capacitor 1000uF at power supply terminal for power line coupling if the traces from amplifier to

speakers are short (< 20CM). Most applications require a ferrite bead filter as shown at Figure 1. The ferrite filter reduces EMI around 1MHz

and higher. When selecting a ferrite bead, choose one with high impedance at high frequencies, and low impedance at low frequencies

(MH2012HM221-T).

Figure 1. Ferrite Bead Filter to Reduce EMI