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UTC LM386
LINEAR INTEGRATED CIRCUIT
LOW VOLTAGE AUDIO POWER
AMPLIFIER
SOP-8
DESCRIPTION
The UTC LM386 is a power amplifier, designed for
use in low voltage consumer applications. The gain is
internally set to 20 to keep external part count low, but
the addition of an external resistor and capacitor
between pin 1 and pin 8 will increase the gain to any
value up 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 voltage supply, making the
LM386 ideal for battery operation.
TSSOP-8
DIP-8
FEATURES
*Battery operation
*Minimum external parts
*Wide supply voltage range: 4V~12V
*Low quiescent current drain:4mA
*Voltage gains:20~200
*Ground referenced input
*Self-centering output quiescent voltage
*Low distortion:0.2%(Av =20,Vs=6V,RL=8
Ω,Po=125mW,f=1kHz)
APPLICATIONS
PIN CONFIGURATIONS
*AM-FM radio amplifiers
*Portable tape player amplifiers
*Intercoms
*TV sound systems
*Line drivers
*Ultrasonic drivers
*Small servo drivers
*Power converters
UTC
Gain
1
-Input
2
8
Gain
7
Bypass
UTC LM386
+Input
3
6
VCC
GND
4
5
Output
UNISONIC TECHNOLOGIES
CO., LTD.
1
QW-R107-007,E
UTC LM386
LINEAR INTEGRATED CIRCUIT
EQUIVALENT SCHEMATIC AND CONNECTION DIAGRAMS
6
BYPASS
15K
7
15K
GAIN GAIN
8
1
150
-INPUT
Vs
15K
5
VOUT
1.35K
2
3
+INPUT
50K
50K
4
GND
ABSOLUTE MAXIMUM RATINGS (Note 2)
PARAMETER
SYMBOL
VALUE
UNIT
Vcc
15
V
Vi
Topr
Tstg
Tj
1250
600
600
-0.4V~+0.4V
0 to 70
-65 to 150
150
mW
mW
mW
V
°C
°C
°C
Supply Voltage
Power Dissipation
DIP-8
SOP-8
TSSOP-8
Input Voltage
Operating Temperature
Storage Temperature
Junction Temperature
ELECTRICAL CHARACTERISTICS (Ta=25°C, Note 1,2)
PARAMETER
SYMBOL
Operating Supply Voltage
Quiescent Current
Output Power
Vs
IQ
Po
Voltage Gain
Gv
Bandwidth
Total Harmonic Distortion
Power Supply Rejection Ratio
BW
THD
PSRR
TEST CONDITIONS
MIN TYP MAX UNIT
4
Vs=6V,VIN=0
Vs=6V,RL=8ΩTHD=10%
Vs=9V,RL=8ΩTHD=10%
Vs=6V,f=1kHz
10µF from pin 1 to pin 8
Vs=6V ,Pin1 and pin 8 open
Po=125mW, Vs=6V,f=1kHz
RL=8Ω pin1 and pin 8 open
Vs=6V,f=1kHz ,CBYPASS=10µF pin1
and pin 8 open, Referred to output
250
500
4
325
700
12
8
V
mA
mW
mW
26
46
300
0.2
dB
dB
kHz
%
50
dB
Input Resistance
RIN
50
kΩ
Input Bias Current
IBIAS
Vs=6V Pin2 and pin 3 open
250
nA
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 functional, but do not guarantee specific performance limits.
Electrical Characteristics state DC and AC electrical specifications under particular 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.
UTC
UNISONIC TECHNOLOGIES
CO., LTD.
2
QW-R107-007,E
UTC LM386
LINEAR INTEGRATED CIRCUIT
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 resistance 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.
APPLICATION HINTS
GAIN CONTROL
To make the LM386 a more versatile amplifier, two pins(1and 8) are provided for gain control. With pins 1 and 8
open the 1.35 kΩ resistor sets the gain at 20(26dB),If a capacitor is put from pin 1 to 8,bypassing the 1.35 kΩ
resistor, the gain will go up to 200(46dB).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.
INPUT BIASING
The schematic shows that both inputs are biased to ground with a 50 kΩ resistor. The base current of the input
transistors is about 250nA, so the inputs are at about 12.5mW when left open. If the dc source resistance driving the
LM386 is higher than 250 kΩ it will contribute very little additional offset (about 2.5mW at the input, 50mW 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 2.5mV at the input,50 mV at the output).For dc source resistances between these values we can
eliminate excess offset by 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.
When using the LM386 with higher gains (bypassing the 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 0.1µF
capacitor or a short to ground depending on the dc source resistance on the driven input.
UTC
UNISONIC TECHNOLOGIES
CO., LTD.
3
QW-R107-007,E
UTC LM386
LINEAR INTEGRATED CIRCUIT
TYPICAL PERFORMANCE CHARACTERISTICS
Power Supply Rejection Ratio(Referred
to the Output) vs Frequency
Quiescent Supply Current vs Supply Voltage
60
6
Power Supply Rejection (dB)
Supply Current (mA)
C7=50μF
5
4
3
2
50
5
6
7
8
9
10
11
1μF
30
0.5μF
10μF
20
NO BYPASSCAPACITOR
10
1
4
Vs=6V
Av=26dB
40
0
10
12
100
1K
10K
100K
Frequency (Hz)
Supply Voltage(volts)
Output Voltage (Volts Peak-To-Peak)
Peak-to -Peak Output Voltage Swing vs Supply Voltage
10
RL=∞
16
8
8
6
4
4
2
0
4
5
6
7
8
9
10
11
12
Supply Voltage(volts)
UTC
UNISONIC TECHNOLOGIES
CO., LTD.
4
QW-R107-007,E
UTC LM386
LINEAR INTEGRATED CIRCUIT
Voltage Gain vs Frequency
Distortion vs Frequency
2.0
60
Total Harmonic Distortion (%)
Voltage Gain (dB)
40
C1.8=0
30
20
10
0
100
1K
10K
Vs=6V
RL=8Ω
POUT=125mW
1.6
Av=26dB(C1.8=0)
1.4
1.8
C1.8=10μF
50
100K
1.2
1.0
0.8
0.6
0.4
0.2
0
20
1M
50 100 200 500 1K 2K
Frequency (Hz)
Frequency (Hz)
Distortion vs Output Power
Device Dissipaton vs Output Power -4ΩLoad
10
8
2.0
Vs=6V
RL=8Ω
f=1kHz
1.8
1.6
Device Dissipation (W)
Total Harmonic Distortion (%)
9
7
6
5
4
3
2
1.4
Vs=12V
1.2
Vs=9V
0.8
0.6
0.4
0
0.01
0.1
0
1.0
0.1
Device Dissipaton vs Output Power -8ΩLoad
0.3
0.4
0.5
Device Dissipaton vs Output Power -16ΩLoad
1.0
1.8
Vs=16V
10% THD
LEVEL
Vs=16V
1.2
Vs=12V
Vs=9V
0.6
0.4
0.2
Vs=6V
0.8
Device Dissipation (W)
1.6
1.4
0
0.2
Output Power (W)
2.0
0.8
10% THD
LEVEL
Vs=6V
Power Output (Watts)
1.0
3% THD
LEVEL
1.0
0.2
1
0
0.001
Device Dissipation (W)
5K 10K 20K
3% THD
LEVEL
3% THD
LEVEL
0.6
Vs=12V
0.4
10% THD
LEVEL
0.2
Vs=9V
Vs=6V
0
0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1.0
0 0.2 0.4 0.6 0.8 1.0 1.2 1.4 1.6 1.8 2.0
Output Power (W)
Output Power (W)
UTC
UNISONIC TECHNOLOGIES
CO., LTD.
5
QW-R107-007,E
UTC LM386
LINEAR INTEGRATED CIRCUIT
TYPICAL APPLICATIONS
Amplifier with Gain=20
Minimum Parts
Amplifier with Gain=200
Vs
6
2
-
6
2
1
VIN
7
8
5
3 +
4
10K
10μF
+
Vs
-
1
250μF
+
VIN
0.05μF
8
5
7
3 +
4
10K
250μF
+
0.05μF
BYPASS
10
10
Amplifier with Gain=50
Low Distortion Power Wienbridge Oscillator
390
Vs
1.2K
10μF
+
Vs
-
1
VIN
7
3 +
4
10K
10μF
6
2
8
5
250μF
+
2
10
6
-
1
ELDEMA
CF-S-2158
BYPASS
0.05μF
3V-15mA
8
5
4
0.01μF
3 +
7
47K
Amplifier with Bass Boost
Vs
BYPASS
6
2
7
250μF
+
8
0.05μF
3 +
4
50μF
8 +
5
RL
VO
RL
10K
10Ω
UTC
1
VO
1 0.033μF
10K
30K
6
-
0.1μF
5
3 +
4
10
Square Ware Oscillator
Vs
10K
Vo
RL
0.01μF
4.7K
-
0.05μF
BYPASS
f=1kHz
2
50μF
+
1K
UNISONIC TECHNOLOGIES
f=1kHz
CO., LTD.
6
QW-R107-007,E
UTC LM386
LINEAR INTEGRATED CIRCUIT
Frequency Response With Bass Boost
27
26
Voltage Gain (dB)
25
24
23
22
21
20
19
18
17
20
50 100 200 500 1K 2K
5K 10K 20K
Frequency (Hz)
AM Radio Power Amplifier
FROM
DETECTOR
Vs
Cc
VOL
10K
R1
10K
10μF
+
0.05μF
2
C1
2200pF
6
-
FERRITE
BEAD
1
250μF
+
8 5
7
3 +
4
+10μF
+
47
8Ω
SPEAKER
0.05μF
Note 4: Twist Supply lead and supply ground very tightly.
Note 5: Twist speaker lead and ground very tightly.
Note 6: Ferrite bead in Ferroxcube K5-001-001/3B with 3 turns of wire.
Note 7: R1C1 band limits input signals.
Note 8: All components must be spaced very closely to IC.
UTC
UNISONIC TECHNOLOGIES
CO., LTD.
7
QW-R107-007,E
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