PAM8906

Document number: DS44739 Rev. 1 - 2

6 of 11

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December 2022

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PAM8906

Application Information

Overview

The PAM8906 is a piezo sounder driver with integrated boost converter. This versatile device is capable of driving piezo sounder for a variety of

applications, including smoke/gas alarm, air humidifier and haptic-feedback related applications. PAM8906 comes in three different Boost output

voltage versions: 10V, 12V, and 18V. A typical start-up time of 770µs makes the PAM8906 an ideal piezo driver with fast response. PAM8906 has

a built-in thermal overload protection, current limit and various other protection features to prevent the device from damage when overdriven.

LDO Regulator

The PAM8906 has a built-in internal LDO regulator to supply 5V to the internal boost and piezo driver blocks. It is recommended to add 1

μF

capacitor at pin 1 VCC (LDO).

VCC

LDO

1

µF

Piezo Driver

As illustrated below, PAM8906 has a built-in Piezo driver circuitry to enable easy system configuration for driving a two-terminal or three-terminal

piezo sounder with few external components. For three-terminal based piezo sounder configuration (supported only by 10V and 12V versions), the

external resistance might vary by piezo sounder manufacturer

’s suggestion. Please consult with Diodes Incorporated’s technical support team or

field representative for any further assistance, if necessary.

OUTP

OUTN

IN

Piezo Driver

FB

OUTP

OUTN

IN

M

F

G

150K

1nF

1.5M

Piezo Driver

DIN Control

DIN pin serves two functions:

1.

Automatic Wake-Up and Shutdown Control

When DIN is set above VIH or provided with a PWM input, PAM8906’s Boost and Piezo driver block will be enabled and the Boost output

will be ready in 770µs (Typ) followed by PWM output on OUTP and OUTN pins.

When DIN is set below VIL the piezo sounder driver will stop immediately.

When DIN is set below VIL for longer than 100ms (Typ), PAM8906’s Boost and Piezo driver will be disabled and the device automatically

enters shutdown mode. PAM8906

’s shutdown current is less than 1μA under this mode.

2.

External PWM Control

For external PWM configuration, DIN pin also serves as the PWM input pin. In this configuration, PWM input is amplified and driven to

OUTP and OUTN pins.

150k