The MSA180 is a piezo speaker driver for OKI's speech synthesizers. Its voltage gain can be adjusted
by a factor of up to 10. The differential output provides an amplitude of twice the voltage supply.
A separate output connects to the base of an external transistor for controlling system voltage.
A standby function eliminates power loss when no input signal is present.
FEATURES
• Power supply voltage: 2.0 V to 6.0 V (single supply voltage)
• Low current consumption: 4.2 mA typ (VCC=3 V, no load)
• Standby current: <1 mA
• Differential output: Twice the supply voltage (maximum output
amplitube)
This pin switches the device between operation and standby modes.
The IC is in operation mode if V
standby mode if V
IL
MODE2 must be connected to V
This pin switches the device between operation and standby modes.
The IC is in operation mode if V
standby mode if V
IH
MODE1 must be connected to GND.
This pin is connected to the base of an external transistor. If an
external transistor is not used to control system voltage, this pin must
be left open.
This is a speaker output pin that provides signals with the same phase
as the input.
This is a speaker output pin that provides signals with an inverted
phase to the input.
< 0.3 V on the MODE1 pin. When MODE1 is used,
> VCC–0.3 V on MODE1 pin. When MODE2 is used
> 1.0 V on the MODE1 pin and is in
IH
.
CC
< VCC–1.0 V on MODE1 pin and is in
IL
2/16
Page 3
ABSOLUTE MAXIMUM RATINGS
ParameterSymbolConditionRatingUnitRemarks
Power Supply VoltageV
Input VoltageV
Maximum Output CurrentI
OMAX
Power DissipationP
Junction TemperatureT
Storage TemperatureT
CC
IN
D
jMAX
STG
—–0.3 to +6.5V—
—–0.3 to VCC+0.3V
VCC=3 V±80mASP, SP
Ta=25°C
—110°CChip
—–55 to +150°C—
RECOMMENDED OPERATING CONDITIONS
MSA180¡ Semiconductor
(Ta=25°C unless otherwise specified)
A
IN
MODE1
MODE2
BASE
400mWDIP type
340mWSOP type
ParameterSymbolMin.Max.UnitCondition
Power Supply VoltageV
Load ImpedanceZ
Peak Load CurrentI
V
"H" Input Voltage
V
V
"L" Input Voltage
V
Operating TemperatureT
CC
O-P
IH1
IH2
IL1
IL2
op
L
Applied to MODE1 pin
Applied to MODE2 pin
Applied to MODE1 pin
Applied to MODE2 pin
Gain control adjustment of the input signal level is shown below. When using OKI's speech
synthesizer devices, insert a diode in series with the variable resistor to reduce pop noise.
V
DD
Signal
R1
100 kW
C1
0.1 mF
BASE
MODE2
A
IN
MODE1
V
MSA180
CC
PIEZO SPEAKER
SP
SP
GND
The circuit below also implements gain adjustment for a higher impedance signal source.
V
DD
Signal
R1
20 kW
C1
0.1 mF
BASE
MODE2
A
IN
MODE1
V
MSA180
GND
CC
PIEZO SPEAKER
SP
SP
5/16
Page 6
MSA180¡ Semiconductor
How to Connect the Piezo Speaker
To achieve the full gain level of 10 V, even at a low supply voltage (VCC=3 V), connect a coil in series
with the piezo speaker.
V
DD
BASE
MODE2
A
IN
MODE1
V
MSA180
CC
SP
SP
COIL
PIEZO SPEAKER
GND
The resonance frequency that occurs in the circuit containing the coil and the piezo speaker is :
fQ =
2p C
1
L
¥ L
[Hz]
L
Where CL is the piezo capacitance and LL the coil inductance.
For instance, if the piezo capacitance is 0.1 mF and fQ is in a range of 2 to 3 kHz, then the coil inductance should be 30 mH.
6/16
Page 7
MSA180¡ Semiconductor
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
V
DD
V
DD
MSM6378A
or MSM6379
GND
AOUT
R2R1
C2
C1
MODE2
A
MODE1
BASEV
MSA180
IN
GND
CC
PIEZO SPEAKER
SP
SP
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.
7/16
Page 8
MSA180¡ Semiconductor
Supplemental Information When Using a Voice Signal on the MODE1 Pin
When using the voice signal on MODE1, as in the circuit below, care must be taken regarding the
voice input level. Application of the voice signal below V
level to the MODE1 pin causes the
IH1
MSA180 to switch into standby mode, interrupting the voice reproduction flow, and causing
undesired noises.
V
DD
Signal
R1
C1
MODE2
A
MODE1
BASEV
MSA180
IN
CC
PIEZO SPEAKER
SP
SP
GND
When using a voice signal lower than VIH, refer to the circuit below. With a low-pass filter consisting
of R2 and C2, voice levels lower than V
such that the input voltage on MODE1 is greater than V
Signal
R2R1
are passed through. However, select values for R2 and C2
IH1
.
IH2
V
DD
BASEV
MODE2
C1
A
IN
MSA180
CC
PIEZO SPEAKER
SP
SP
C2
MODE1
GND
The cutoff frequency of the low-pass filter is calculated as follows:
fC =
1
2p ¥ R2
¥ C2
[Hz]
For instance, if the cutoff frequency is 50 Hz, C2 is 0.1 mF and R2 is 30 kW. For a lower cutoff frequency, use a larger value for C2 or R2.
8/16
Page 9
MSA180¡ Semiconductor
Application Example for Circuits Containing MSM6375/MSM6650 Family Speech Synthesizers
The example below shows how to connect the MSA180 with the MSM6375 or MSM6650 family
speech synthesizers using the synthesizer's BUSY output to control operation and standby mode of
the MSA180. As voice output stops, BUSY rises to the "H" level. For this reason, MODE2 is used to
control operation and standby modes of the MSA180.
V
DD
V
DD
MSM6650
or MSM6375
GND
AOUT
BUSY
R1
C1
MODE2
A
MODE1
BASEV
MSA180
IN
GND
CC
PIEZO SPEAKER
SP
SP
Notes: 1. The diode on A
2. This circuit makes use of the BUSY output of the speech synthesizer.
3. As the voice reproduction stops, BUSY outputs a "H" level to MODE2, setting the stand-
by function.
4. If MODE2 is used, MODE1 must be connected to GND.
5. Leave the BASE pin open if it is not used.
reduces pop noise.
OUT
9/16
Page 10
MSA180¡ Semiconductor
Application Example for Circuits Containing the MSM6388/MSM6588 Speech Recorders
The example below shows how to connect the MSA180 with the MSM6388 or MSM6588 family
speech recording ICs using the recorders' STBY output to control operation and standby mode of the
MSA180. As voice output stops, STBY rises to the "H" level. For this reason, MODE2 is used to control
operation and standby modes of the MSA180.
V
DD
V
DD
MSM6388
or MSM6588
GND
AOUT
CS3(STBY)
R1
C1
MODE2
A
MODE1
BASEV
MSA180
IN
GND
CC
PIEZO SPEAKER
SP
SP
Notes: 1. The diode on A
2. This circuit makes use of the STBY output of the speech synthesizer.
3. As the voice reproduction stops, STBY outputs a "H" level to MODE2, setting the standby function.
4. If MODE2 is used, MODE1 must be connected to GND.
5. Leave the BASE pin open if it is not used.
reduces pop noise.
OUT
10/16
Page 11
MSA180¡ Semiconductor
Application Examples for Circuits Containing a Microcontroller or Other Peripheral
Devices
The circuit below uses a voice signal which rises high in operation mode. The MODE1 pin is used.
Be sure to connect the MODE2 pin to VCC pin.
V
DD
Signal
BASEV
MODE2
CC
PIEZO SPEAKER
SP
C1
Control Signal Input
R1
A
MODE1
IN
MSA180
SP
GND
Note:If the BASE pin is not used, leave it open.
In the circuit below, the signal falls low in operation mode. The MODE2 pin is used. Be sure to
connect the MODE1 pin to the GND pin.
Package material
Lead frame material
Pin treatment
Solder plate thickness
Package weight (g)
Epoxy resin
42 alloy
Solder plating
5 mm or more
0.46 TYP.
15/16
Page 16
SOP8-P-250-1.27-K
Mirror finish
MSA180¡ Semiconductor
(Unit : mm)
Package material
Lead frame material
Pin treatment
Solder plate thickness
Package weight (g)
Epoxy resin
42 alloy
Solder plating
5 mm or more
0.10 TYP.
Notes for Mounting the Surface Mount Type Package
The SOP, QFP, TSOP, TQFP, LQFP, SOJ, QFJ (PLCC), SHP, and BGA are surface mount type
packages, which are very susceptible to heat in reflow mounting and humidity absorbed in
storage. Therefore, before you perform reflow mounting, contact Oki’s responsible sales person
on the product name, package name, pin number, package code and desired mounting conditions
(reflow method, temperature and times).
16/16
Page 17
E2Y0002-29-11
NOTICE
1.The information contained herein can change without notice owing to product and/or
technical improvements. Before using the product, please make sure that the information
being referred to is up-to-date.
2.The outline of action and examples for application circuits described herein have been
chosen as an explanation for the standard action and performance of the product. When
planning to use the product, please ensure that the external conditions are reflected in the
actual circuit, assembly, and program designs.
3.When designing your product, please use our product below the specified maximum
ratings and within the specified operating ranges including, but not limited to, operating
voltage, power dissipation, and operating temperature.
4.Oki assumes no responsibility or liability whatsoever for any failure or unusual or
unexpected operation resulting from misuse, neglect, improper installation, repair, alteration
or accident, improper handling, or unusual physical or electrical stress including, but not
limited to, exposure to parameters beyond the specified maximum ratings or operation
outside the specified operating range.
5.Neither indemnity against nor license of a third party’s industrial and intellectual property
right, etc. is granted by us in connection with the use of the product and/or the information
and drawings contained herein. No responsibility is assumed by us for any infringement
of a third party’s right which may result from the use thereof.
6.The products listed in this document are intended for use in general electronics equipment
for commercial applications (e.g., office automation, communication equipment,
measurement equipment, consumer electronics, etc.). These products are not authorized
for use in any system or application that requires special or enhanced quality and reliability
characteristics nor in any system or application where the failure of such system or
application may result in the loss or damage of property, or death or injury to humans.
Such applications include, but are not limited to, traffic and automotive equipment, safety
devices, aerospace equipment, nuclear power control, medical equipment, and life-support
systems.
7.Certain products in this document may need government approval before they can be
exported to particular countries. The purchaser assumes the responsibility of determining
the legality of export of these products and will take appropriate and necessary steps at their
own expense for these.
8.No part of the contents cotained herein may be reprinted or reproduced without our prior
permission.
9.MS-DOS is a registered trademark of Microsoft Corporation.
Copyright 1999 Oki Electric Industry Co., Ltd.
Printed in Japan
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