MSA180 View Datasheet(PDF) - Oki Electric Industry

Part Name

Description

Manufacturer

MSA180

Piezo Speaker Amplifier

Oki Electric Industry 

¡ Semiconductor

MSA180

Application Example for Circuits Containing the MSM6378A/MSM6379 Speech Synthesizers

This example shows how to connect the MSA180 with an MSM6378A or MSM6379 speech

synthesizer using an external transistor and the MODE1 pin. The analog output of both synthesizers

lowers to 0 V in their standby mode. For this reason, the voice signal can be used to control operation

and standby modes of the MSA180. The circuit also controls the voltage via an external transistor.

If this function is not used, leave the BASE pin open.

START SWITCH

VDD

VDD

AOUT

MSM6378A

or MSM6379

R2

R1

BASE

MODE2

VCC

PIEZO SPEAKER

SP

C1 AIN MSA180

GND

MODE1

SP

C2

GND

Operation Flow

1. When the start switch is pressed, power is supplied to the VDD pins on the MSM6378A or

MSM6379, and operation mode is invoked. Voice output level then rises.

2. When operation mode is involved, the voice signal rises above the GND level, and MODE1 on

MSA180 goes high (H).

3. The BASE pin on MSA180 goes low (L) to drive the external transistor for power-supply control.

4. The audio IC continues to operate using the external transistor as a power supply. The device

continues to operate and voice sounds, even if the start switch is released at this time.

5. When the sound ends, MODE1 on MSA180 falls low (L), the voice signal falls to GND level, and

standby mode ensues.

6. The external transistor for power-supply control is switched off, switching the voice synthesizer

off because the power supply is switched off.

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