PAM8303C

Document number: DS36438 Rev.2 - 2

11 of 16

www.diodes.com

May 2018

© Diodes Incorporated

PAM8303C

The PAM8303C is a high-performance CMOS audio amplifier that requires adequate power-supply decoupling to ensure the output total

harmonic distortion (THD) as low as possible. Power-supply decoupling also prevents the oscillations caused by long lead length between the

amplifier and the speaker.

The optimum decoupling is achieved by using two different types of capacitors that target on different types of 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

a large ceramic capacitor of 10µF or greater placed near the audio power amplifier is recommended.

How to Reduce EMI

Most applications require a ferrite bead filter for EMI elimination as shown in Figure 1. The ferrite filter reduces EMI around 1MHz and higher.

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

Figure 1: Ferrite Bead Filter to Reduce EMI

In order to reduce power consumption while not in use, the PAM8303C contains shutdown circuitry that is used to turn off the

amplifier’s bias

circuitry. This shutdown feature turns the amplifier off when logic low is placed on the SD pin. By switching the shutdown pin connected to GND,

the PAM8303C supply current draw is minimized in idle mode.

Shutdown Operation

In order to reduce power consumption while not in use, the PAM8303C contains shutdown circuitry that is used to turn off the amp

lifier’s bias

circuitry. This shutdown feature turns the amplifier off when logic low is placed on the pin. By switching the shutdown pin connected to GND, the

PAM8303C supply-current draw will be minimized in idle mode.

Undervoltage Lockout (UVLO)

The PAM8303C incorporates circuitry designed to detect low supply voltage. When the supply voltage drops to 2.3V or below, the PAM8303C

goes into a state of shutdown, and the device comes out of its shutdown state and restores to normal function only when reset the power supply

or SD pin.

Thermal protection on the PAM8303C prevents the device from damage when the internal die temperature exceeds +135°C. There is a 15°C

tolerance on this trip point from device to device. Once the die temperature exceeds the set point, the device enters the shutdown state, and the

outputs are disabled. This is not a latched fault. The thermal fault is cleared once the temperature of the die decreases by 30°C. This large

hysteresis prevents motor-boating sound, and the device begins normal operation at this point with no external system interaction.

Pop and Click Circuitry

The PAM8303C 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 recovery from shutdown mode. When the device is turned on, the amplifiers are internally muted. An internal current source ramps

the reference voltage is stable, the device begins full operation. For the best power-off pop performance, the amplifier should be set in shutdown

mode prior to removing the power-supply voltage.