PAM8902

30-Vpp Mono Class-D Audio Amplifier for Piezo/Ceramic Speakers

9

,

Power Analog Microelectronics Inc

www.poweranalog.com

01/2012 Rev1.4

Application Information

good low equivalent series-resistance (ESR) ceramic capacitor, typically 1 F, is placed as close as

possible to the device AVDD pin for the best operation. For filtering lower frequency noise signals , a large

ceramic capacitor of 10 F or greater placed near the AVDD supply trace is recommended.

Use external schottky diode can get the best driving capability and efficiency.

Since internal power diode has limited driving capability ,only in following conditions customer ca n remove

the external schottky diode to reduce the cost.

1. Vset = GND or Floating and C less than 1uF.

2. The signal frequency less than 4KHz.

3. Haptic application (50-500Hz)

In order to reduce power consumption while not in use, the PAM8902 contains shutdown circuitry amplifier

off when a logic low is placed on the ENA pin. By switching the ENA pin connected to GND, the PAM89 02

supply current draw will be minimized in idle mode.

The PAM8902 incorporates circuitry designed to detect supply voltage. When the supply voltage dro ps to

2.2V or below, the PAM8902 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 ENA pin.

The PAM8902 has short circuit protection circuitry on the outputs to prevent the device from damage when

output-to-output shorted or output-to-GND shorted occurs. When a short circuit occurs, the device goes

into a latch state and must be reset by cycling the voltage on the ENA pin to a logic low and then back to the

logic high state for normal operation. This will clear the short-circuit flag and allow for normal operation if

the short was removed. If the short was not removed, the protection circuitry will again activate.

Thermal protection on the PAM8902 prevents the device from damage when the internal die temperature

exceeds 150°C. There is a 15°C tolerance on this trip point from device to device. Once the die tem perature

exceeds the set point, the device will enter the shutdown state and the outp uts are disabled,in this

condition both OUT+ and OUT- will become high impedance. This is not a latched fault. The thermal f ault is

cleared once the temperature of the die decreased by 30°C. This large hysteresis will prevent motor

boating sound well and the device begins normal operation at this point with no external system int eraction.

μ

μ

External Schottky Diode

Shutdown operation

Under Voltage Lock-out (UVLO)

Short Circuit Protection (SCP)

Over Temperature Protection (OTP)

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