PAM8303DAYN datasheet(13/17 Pages) PAM

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PAM8303D

Ultra Low EMI, 3W Filterless

Mono Class-D Audio Power Amplifier

amplifier off when logic low is placed on the

pin. By switching the shutdown pin connected to

GND, the PAM8303D supply current draw will be

minimized in idle mode.

°C

internal

associated

(VDD and PVDD)

(10 F

or greater)

Output filter - The ferrite EMI filter should be

placed as close to the output terminals as

possible for the best EMI performance, and the

capacitors used in the filters should be grounded

to system ground.

Under Voltage Lock-out (UVLO)

Short Circuit Protection (SCP)

Over Temperature Protection (OTP)

POP and Click Circuitry

PCB Layout Guidelines

Grounding

Power Supply Line

Components Placement

The PAM8303D incorporates circuitry designed

to detect low supply voltage. When the supply

voltage drops to 2.3V or below, the PAM8303D

goes into a state of shutdown, and the device

comes out of its shutdown state and restore to

normal function only when reset the power

supply or

pin.

The PAM8303D has short circuit protection

circuitry on the outputs to prevent the device

from damage when output-to-output shorts or

output-to-GND shorts occur. When a short circuit

occurs, the device i mmediately goes into

shutdown state. Once the short is removed, the

device will be reactivated.

Thermal protection on the PAM8303D prevents

the device from damage when the internal die

temperature exceeds 135°C. There is a 15

tolerance on this trip point from device to device.

Once the die temperature exceeds the set point,

the device will enter the shutdown state and the

outputs are disabled. This is not a latched fault.

The

t hermal

f ault

cleared

once

t he

temperature of the die decreased by 30

. This

large hysteresis will prevent motor boating sound

well and the device begins normal operation at

this point with no external system interaction.

The PAM8303D contains circuitry to minimize

turn-on and turn-off transients or “click and

pops”, where turn-on refers to either power

supply turn-on or device recover from shutdown

mode. When the device is turned on, the

amplifiers are internally muted. An internal

current source ramps up the

reference

voltage. The device will remain in mute mode

until the reference voltage reach half supply

voltage, 1/2 VDD. As soon as the reference

voltage is stable, the device will begin full

operation.

For

t he

best

power-of f

pop

performance, the amplifier should be set in

shutdown mode prior to removing the power

supply voltage.

It is recommended to use plane grounding or

separate g rounds. D o not use one line

connecting power GND and analog GND. Noise

currents in the output power stage need to be

returned to output noise ground and nowhere

else. When these currents circulate elsewhere,

they may get into the power supply, or the signal

ground, etc, even worse, they may form a loop

and radiate noise. Any of these instances results

in degraded amplifier performance. The output

noise ground that the logical returns for the

output noise currents

with class D

switching must tie to system ground at the power

exclusively. Signal currents for the inputs,

reference need to be returned to quite ground.

This ground only ties to the signal components

and the GND pin. GND then ties to system

ground.

As same to the ground, VDD and PVDD need to

be separately connected to the system power

supply. It is recommended that all the trace could

be routed as short and thick as possible. For the

power line layout, just imagine water stream, any

barricade placed in the trace (shown in figure 2)

could result in the bad performance of the

amplifier.

Figure 2: Power Line

Decoupling capacitors-As previously described,

the high-frequency 1 F decoupling capacitors

should be placed as close to the power supply

terminals

as possible. Large

bulk power supply decoupling capacitors

should be placed near the PAM8303D

on the PVDD terminal.

Input resistors and capacitors need to be placed

very close to input pins.

°C

Power Analog Microelectronics Inc

www.poweranalog.com

09/2008 Rev 1.4

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