Wing Shing LM386M-1, LM386N-1 Datasheet

Low Voltage Audio Power Amplifier

Low Voltage
Audio Power Amplifier

WS386M-1 ideal for battery operation

Pin Connection

Dual in Line Package

and DIP package

Ordering Information

PART NO.

PACKAGE

SOP-8

DIP-8

8-1

LM386-1

The LM386-1

LM386M-1

LM386N-1

General Description

isapoweramplifierdesignedforuseinlowvolt­ageconsumerapplications.Thegainisinternallysetto20to
keep external part count low, but the addition of an external
resistor andcapacitor between pins 1 and 8 will increase the
gain to any value from 20 to 200.

The inputs are ground referenced while the output automati­cally biases to one-half the supply voltage. The quiescent
power drain is only 24 milliwatts when operating from a 6 volt
supply,makingthe

Features

n Battery operation
n Minimum external parts
nWidesupplyvoltagerange:4V–12V
n Low quiescent current drain: 4mA
n Voltage gains from 20 to 200
n Ground referenced input
n Self-centering output quiescent voltage
n Low distortion: 0.2% (A

125mW, f = 1kHz)

nAvailablein8pinSOPpackage

Applications

nAM-FMradioamplifiers
nPortabletapeplayeramplifiers
nIntercoms
nTVsoundsystems
nLinedrivers
nUltrasonicdrivers
nSmallservodrivers

nPowerconverters

Equivalent Schematic and Connection Diagrams

= 20, VS=6V,RL=8Ω,PO=

V

Small Outline,

Wing Shing Computer Components Co., (H.K.)Ltd. Tel:[phone] Fax:[phone]
Homepage: http://www.wingshing.com E-mail: [e-mail]

AbsoluteMaximumRatings

4

12

V

V

,Vcc=6V,R =8 ,f=1KH , unless otherwise specified

Z

Pins 1 and 8 Open

15V

Soldering Information

Supply Voltage

(WS386-1)

Package Dissipation(Note3)

(WS386N) 1.25W

0.73W

(WS386M)

.4V

+

-

65 C to +150 C

0 C to+70 C

+150 C

Input Voltage

Storage Temperature

Junction Temperature

Operating Temperature

-

8-2

LM386-1

50

700

V s = 9V,RL =8 , THD =10%

Bandwidth (BW)

Vs = 6V,10uF from Pin 1 to 8

60

kHz

Electrical Characteristics (Notes 1, 2)

TA= 25˚C

Parameter Conditions Min Typ Max Units

Operating Supply Voltage (V

)

S

Dual-In-LinePackage

Soldering (10 sec) +260˚C

Small Outline Package

(SOIC)
Vapor Phase (60 sec) +215˚C
Infrared (15 sec) +220˚C

Quiescent Current (I
Output Power (P

Voltage Gain (A

)V

Q

)

OUT

)V

V

= 6V, VIN=0 4 8 mA

S

= 6V, RL=8Ω, THD = 10% 250 325 mW

S

= 6V, f = 1 kHz 26 dB

S

10 µF from Pin 1 to 8 46 dB
Bandwidth (BW) V
Total Harmonic Distortion (THD) V

= 6V, Pins 1 and 8 Open 300 kHz

S

= 6V, RL=8Ω,P

S

= 125 mW 0.2 %

OUT

f = 1 kHz, Pins 1 and 8 Open
Power Supply Rejection Ratio (PSRR) V

= 6V, f = 1 kHz, C

S

=10µF 50 dB

BYPASS

Pins 1 and 8 Open, Referred to Output
Input Resistance (R
Input Bias Current (I

Note 1: All voltages are measured with respect to the ground pin, unless otherwise specified.
Note 2: Absolute Maximum Ratings indicate limitsbeyond which damage to the device mayoccur. Operating Ratings indicateconditions for which the device is func-

tional, butdo not guarantee specific performance limits.Electrical Characteristics state DC andAC electrical specificationsunderparticular test conditions which guar­antee specific performance limits. This assumes that the device is within the Operating Ratings. Specifications are not guaranteed for parameters where no limit is
given, however, the typical value is a good indication of device performance.

Note3:Foroperationinambienttemperaturesabove25˚C,thedevicemustbederatedbasedona150˚Cmaximumjunctiontemperatureand
athermalresistanceof170˚C/Wforthesmalloutlinepackage.

) 50 kΩ

IN

)V

BIAS

= 6V, Pins 2 and 3 Open 250 nA

S

Application Hints

876

1905902

3

8-3

LM386-1

To make LM386-1

When using LM386-1

GAIN CONTROL

amoreversatileamplifier,twopins(1
and 8) are provided for gain control. With pins 1 and 8 open
the 1.35 kΩ resistor sets the gain at 20 (26 dB). If a capacitor
is put from pin 1 to 8, bypassing the 1.35 kΩ resistor, the
gain will go up to 200 (46 dB). If a resistor is placed in series
with the capacitor, the gain can be set to any value from 20
to 200. Gain control can also be done by capacitively cou­pling a resistor (or FET) from pin 1 to ground.

Additional external components can be placed in parallel
with the internal feedback resistors to tailor the gain and fre­quency response for individual applications. For example,
we can compensate poor speaker bass response by fre­quency shaping the feedback path. This is done with a series
RC from pin 1 to 5 (paralleling the internal 15 kΩ resistor).
For 6 dB effective bass boost: R . 15 kΩ, the lowest value
for good stable operation is R = 10 kΩ if pin 8 is open. If pins
1 and 8 are bypassed then R as low as 2 kΩ can be used.
This restriction is because the amplifier is only compensated
for closed-loop gains greater than 9.

Pad Location

INPUT BIASING

The schematic shows that both inputs are biased to ground
witha50kΩresistor. The base current of the input transis-
tors is about 250 nA, so the inputs are at about 12.5 mV
when left open. If the dc source resistance driving the LM386
is higher than 250 kΩ it will contribute very little additional
offset (about 2.5 mV at the input, 50 mV at the output). If the
dc source resistance is less than 10 kΩ, then shorting the
unused input to groundwill keep the offset low (about 2.5 mV
at the input, 50 mV at the output). For dc source resistances
between these values we can eliminate excess offsetby put­ting a resistor from the unused input to ground, equal in
value to the dc source resistance. Of course all offset prob­lems are eliminated if the input is capacitively coupled.

withhighergains(bypassingthe

1.35 kΩ resistor between pins 1 and 8) it is necessary to by­pass the unused input, preventing degradation of gain and
possible instabilities. This is done with a 0.1 µF capacitor or
a short to ground depending on the dc source resistance on
the driven input.

Y

0

X

Pad Location Coordinates

Pad N Pad Name

1
2

3
4A
4B

5

6

7

8

Gain

-input
+input

GND
GND

VOUT

V

CC

BYPASS

Gain

4B

4A

Chip size 1.4 x 1.6 mm

Coordinates

XY
120
120
120
550
600
600
750
440
120

975
665
100
100

390
1015
1405
1405
1405