If Military/Aerospace specified devices are required,
please contact the National Semiconductor Sales Office/
Distributors for availability and specifications.
Supply Voltage
(LM386N-1, -3, LM386M-1)
Supply Voltage (LM386N-4)
Package Dissipation (Note 3)
(LM386N)
(LM386M)
(LM386MM-1)
Input Voltage
Storage Temperature
Operating Temperature
Junction Temperature
Soldering Information
15V
22V
1.25W
0.73W
0.595W
±
0.4V
−65˚C to +150˚C
0˚C to +70˚C
+150˚C
Dual-In-Line Package
Soldering (10 sec)
+260˚C
Small Outline Package
(SOIC and MSOP)
Vapor Phase (60 sec)
+215˚C
Infrared (15 sec)
+220˚C
See AN-450 “Surface Mounting Methods and Their Effect
on Product Reliability” for other methods of soldering
surface mount devices.
Thermal Resistance
37˚C/W
θ
JC
(DIP)
107˚C/W
θ
JA
(DIP)
35˚C/W
θ
JC
(SO Package)
172˚C/W
θ
JA
(SO Package)
210˚C/W
θ
JA
(MSOP)
56˚C/W
θ
JC
(MSOP)
Electrical Characteristics
(Notes 1, 2)
T
A
= 25˚C
Parameter
Operating Supply Voltage (V
S
)
LM386N-1, -3, LM386M-1, LM386MM-1
LM386N-4
Quiescent Current (I
Q
)
Output Power (P
OUT
)
LM386N-1, LM386M-1, LM386MM-1
LM386N-3
LM386N-4
Voltage Gain (A
V
)
Bandwidth (BW)
Total Harmonic Distortion (THD)
Power Supply Rejection Ratio (PSRR)
Input Resistance (R
IN
)
Input Bias Current (I
BIAS
)
V
S
= 6V, Pins 2 and 3 Open
Note 1:
All voltages are measured with respect to the ground pin, unless otherwise specified.
Note 2:
Absolute Maximum Ratings indicate limits beyond which damage to the device may occur. Operating Ratings indicate conditions for which the device is func-
tional, but do not guarantee specific performance limits. Electrical Characteristics state DC and AC electrical specifications under particular test conditions which guar-
antee 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.
Note 3:
For operation in ambient temperatures above 25˚C, the device must be derated based on a 150˚C maximum junction temperature and 1) a thermal resis-
tance of 107˚C/W junction to ambient for the dual-in-line package and 2) a thermal resistance of 170˚C/W for the small outline package.
Conditions
Min
4
5
Typ
Max
12
18
Units
V
V
mA
mW
mW
mW
dB
dB
kHz
%
dB
kΩ
nA
V
S
= 6V, V
IN
= 0
V
S
= 6V, R
L
= 8Ω, THD = 10%
V
S
= 9V, R
L
= 8Ω, THD = 10%
V
S
= 16V, R
L
= 32Ω, THD = 10%
V
S
= 6V, f = 1 kHz
10 µF from Pin 1 to 8
V
S
= 6V, Pins 1 and 8 Open
V
S
= 6V, R
L
= 8Ω, P
OUT
= 125 mW
f = 1 kHz, Pins 1 and 8 Open
V
S
= 6V, f = 1 kHz, C
BYPASS
= 10 µF
Pins 1 and 8 Open, Referred to Output
250
500
700
4
325
700
1000
26
46
300
0.2
50
50
250
8
www.national.com
2
LM386
Application Hints
GAIN CONTROL
To make the LM386 a more versatile amplifier, two pins (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 cou-
pling 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 fre-
quency response for individual applications. For example,
we can compensate poor speaker bass response by fre-
quency 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.
INPUT BIASING
The schematic shows that both inputs are biased to ground
with a 50 kΩ resistor. 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 ground will 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 offset by put-
ting a resistor from the unused input to ground, equal in
value to the dc source resistance. Of course all offset prob-
lems are eliminated if the input is capacitively coupled.
When using the LM386 with higher gains (bypassing the
1.35 kΩ resistor between pins 1 and 8) it is necessary to by-
pass 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
