PAM8603MNHR datasheet(11/14 Pages) PAM

11 / 14 page

Over Temperature Protection

How t o Reduce EMI (Electro Magnetic

Interference)

PCB Layout Guidelines Grounding

Thermal protection on the PAM8603M prevents

the device from damage when the internal die

temperature exceeds 135°C. There is a 15 degree

tolerance on this trip 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 30

This large hysteresis will prevent motor boating

sound well. The device begins normal operation

at this point without external system interaction.

A simple solution is to put an additional capacitor

1000 F 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 3. The ferrite filter reduces EMI of

around 1 MHz and higher. When selecting a ferrite

bead, choose one with high impedance at high

frequencies, and low impedance a t low

frequencies (MH2012HM221-T).

Figure 3: Ferrite Bead Filter to Reduce EMI

At this stage it is paramount to notice the

necessity of separate grounds. Noise currents in

the output power stage need to be returned to

output noise ground and nowhere else. Were

these currents to circulate elsewhere, they may

get into the power supply, the signal ground, etc,

even worse, they may form a loop and radiate

noise. Any of these cases results in degraded

amplifier performance. The logical returns for the

output noise currents associated with Class-D

switching are the respective PGND pins for each

channel. The switch state diagram illustrates that

PGND is instrumental in nearly every switch

state. This is the perfect point to which the output

noise ground trace should return. Also note that

output noise ground is channel specific. A two-

channel amplifier has two seperate channels and

consequently must have two seperate output

noise ground traces. The layout of the PAM8603M

offers separate PGND connections for each

channel and in some cases each side of the

bridge. Output noise grounds must be tied to

system ground at the power exclusively. Signal

currents for the inputs, reference, etc need to be

returned to quite ground. This ground is only tied

to the signal components and the GND pin, and

GND then tied to system ground.

°C

10/2008 Rev 1.0

200pF

OUT+

OUT-

Ferrite Bead

Power Analog Microelectronics Inc

www.poweranalog.com

PAM8603M

3W Filterless Stereo Class-D Audio Amplifier with DC Volume Control

PAM8603MNHR Datasheet(PDF) 11 Page - Power Analog Micoelectronics

PAM8603MNHR Datasheet(HTML) 11 Page - Power Analog Micoelectronics

Html Pages

1 2 3 4 5 6 7 8 9 10 11 12 13 14

Datasheet Download

Link URL