OKI MSC1157MS-K, MSC1157RS Datasheet

E2D0048-39-22

¡ Semiconductor MSC1157

¡ Semiconductor

This version: Feb. 1999

Previous version: May. 1997

MSC1157

Speaker Drive Amplifier

GENERAL DESCRIPTION

The MSC1157, designed specifically to operate at a low voltage with low current consumption, is a power amplifier developed for driving a speaker for a voice IC. The voltage gains can be adjusted over a range of up to ten. The differential output can directly drive a speaker without any output coupling capacitors. The MSC 1157, because of its ability to stand by, is ideally suitable for portable equipment applications powered by a battery.

FEATURES

• Low voltage operation : 2.0 to 6.0 V (Single power supply)

• Low current dissipation Operating current : 1.6mA without load (typ.)

• Standby function : Current dissipation less than 1 mA in standby

• High output current : 350mA peak

• Differential outputs : A speaker can be directly connected between

differential outputs.

• Adjustable gain : Gain can be adjusted by use of an external resistor.

• Package options:

8-pin plastic DIP (DIP8-P-300-2.54) (Product name : MSC1157RS) 8-pin plastic SOP (SOP8-P-250-1.27-K) (Product name : MSC1157MS-K) Chip

BLOCK DIAGRAM

STBY

SEL

GND

Logic

52 kW50 kW

–

20 kW

100 kW

–

5 kW

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¡ Semiconductor MSC1157

PIN CONFIGURATION (TOP VIEW)

PIN DESCRIPTIONS

Symbol

GND — Ground pin.

Type Description

— Power supply pin.

I Signal input pin for analog signal inputs, etc.

GND

SEL

STBY

8-Pin Plastic DIP

8-Pin Plastic SOP

Digital input pins. Setting these pins configures the standby status. See the table below

for how to set the pins.

7, 8

STBY,

SEL

VR O

SEL STBY Status

0 Operation

0 1 Standby

Clock Operation

0 Standby

1 1 Operation

Clock Operation

0 Operation

Clock 1 Operation

Clock

Unstable Operation

Applying a clock between 32kHz and 4MHz to either the STBY or the SEL pin leads the IC

to operation status regardless of the status set at the other pin. Applying clocks to both

of the pins at the same time may cause malfunction.

Refer to the section, RECOMMENDED OPERATING CONDITIONS since clock frequencies

are changed by setting the SEL pin.

Bias output pin for internal circuits. This pin is at GND potential during standby.

Connecting a capacitor between VR and the GND pin reduces the pop-up noise at power

on and improves the ripple elimination ratio.

SP O Speaker output pin. This pin outputs a negative phase with respect to the input signal.

SP O Speaker output pin. This pin outputs a positive phase with respect to the input signal.

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¡ Semiconductor MSC1157

ABSOLUTE MAXIMUM RATINGS

Parameter

Power Supply Voltage V

Symbol

Condition Rating Unit Remark

Ta=25°C –0.3 to +6.5 V V

STBY

Input Voltage V

Ta=25°C –0.3 to VCC+0.3 V

, SEL

(*1)

Maximum Output Current I

OMAX

Ta=25°C

±400 mA SP, SP

470 mW DIP type

Power Dissipation P

Junction Temperature

Storage Temperature

jMAX

STG

Ta=25°C

400 mW SOP type

— 125 °C Chip

— –55 to +150 °C

*1 Avoid shorting the output pins (SP and SP) to VCC or GND because the IC may be damaged.

RECOMMENDED OPERATING CONDITIONS

Parameter

Power Supply Voltage V

Load Impedance (*2) RL

Peak Load Current I

"H" Input Voltage V

"L" Input Voltage V

STBY Operating Frequency (*3) f

Operating Temperature Top

Symbol

O-P

STBY

Condition

—

For STBY and SEL pins

SEL = "L"

At clock input

≥ 2.4 V

SEL = "H"

At clock input

≥ 2.4 V

—

2.0 6.0 V

8.0 — W

— 350 mA

0.7 V

— 0.3 V

—V

32 k 4.096 M

32 k 1 M

–20 +70 °C

UnitMin. Max.

*2 A speaker of 8 W (standard) or more should be used. *3 The input of clocks may cause a little noise in output waveforms.

It is recommended to input the DC voltage to inprove voice quality.

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¡ Semiconductor MSC1157

ELECTRICAL CHARACTERISTICS

Unless otherwise specified, Ta=25°C, V

Parameter Symbol Condition UnitMax.Typ.Min.

Input Resistance R

Voltage Gain A

AINÆ(Between SP-SP) 20.512019.46

—kW262014

AINÆSP 14.491413.44

SPÆSP dB+1.580–1.94

VCC=3 V, f=1 kHz

OUT1

RL=8 W, THD≥10%

Output Power

VCC=6 V, f=1 kHz

OUT2

THD1

Total Harmonic Distortion

THD2

RL=32 W, THD≥10%

=3 V, RL=8 W

f=1 kHz, P

=6 V, RL=32 W

f=1 kHz, P

=45 mW

OUT

=125 mW

OUT

Ripple Elimination Ratio RR f=1 kHz, C2=4.7 mFdB—4330

Output DC Voltage (*4)

Output Offset Voltage DV

signal state

In no

Between SP-SP mV±30——

VCC=2 V 0.770.650.53

=6 V 2.732.612.49

AIN=VCC or GND

=–100 mA

OUT

AIN=VCC or GND

Output "L" Voltage

STBY, SEL

Input Current

VR Equivalent Resistance R

Circuit Current During Operation I

Circuit Current During Standby I

CCS

=100 mA

OUT

VI=V

VI=GND mA±0.1——

—

VCC=6 V, RL=• mA2.41.61.1

— mA1.0——

=2 to 6 V

mW—178100

mW—440300

%—1.2—

%—0.37—

–1.04VCC–1.15Output "H" Voltage

V—V

V0.30.17—

mA±0.1——

kW322518

*4 The typical value of the output voltage in no signal state is determined from the following

equation.

50 kW

VO = (V

– 0.67)

50 kW + 52 kW

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¡ Semiconductor MSC1157

APPLICATION CIRCUIT

C4 C3

–

Standby Select Input

Standby Input

Audio Input

SEL

STBY

–

GND

Speaker

• If parasitic capacitance of 60pF or more exists between GND and the speaker output pin SP or

SP, oscillation may occur. Implement the circuit mount design so as to be less than 60pF.

• C1 is the AC coupling capacitor. Cutoff frequency fc on the low frequency side is determined

by the following equation. Choose a value of C1 according to the bandwidth.

fc =

(Hz)

2 ¥ p ¥ C1 ¥ 20k

• Choose a value of C2 that is 80 to 100 times as large as that of C1.

• When the standby function is not used, connect the pins STBY and SEL to VCC or GND.

• It is recommended that the capacitor C4 (approximately 0.1mF) having better high frequency

characteristics and the capacitor C3 (approximately 10mF) be placed between the pins VCC and GND.

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