Lm386 Audio Amplifier Circuit Diagram With PCB

lm386 audio amplifier circuit diagram with PCB, the 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 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, making the LM386 ideal for battery operation.

The LM386M-1 and LM386MX-1 are power amplifiers designed for use in low voltage equipment. The gain is internally set to 20 to use few external components, but adding an external resistor and capacitor between pins 1 and 8 increases the gain to anywhere from 20 to 200.

LM386N-1, LM386N-3, LM386M-1, LM386MM-1 can use powe supply up to 12V and LM386N-4 up to 18V

Features:

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Battery operation
Minimum external parts
Wide supply voltage range: 4V-12V or 5V-18V
Low quiescent current drain: 4mA
Voltage gains from 20 to 200
Ground referenced input
Self-centering output quiescent voltage
Low distortion: 0.2% (A_V = 20, V_S = 6V, R_L = 8[Ohm], P_O = 125mW, f = 1kHz)
Available in 8 pin MSOP package

Applications

AM-FM radio amplifiers
Portable tape player amplifiers
Intercoms
TV sound systems
Line drivers
Ultrasonic drivers
Small servo drivers
Power converters

Equivalent Schematic lm386 pinout datasheet and Connection Diagrams LM386M-1, LM386MM-1, LM386N-1, LM386N-3 or LM386N-4

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 (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 20to 200.

Gain control can also be done by capacitive 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 program.

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 pins1 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.

Schematic of power audio amplifier for applications as Amplifiers of radio FM, Amplifiers of MP3 portable players, Intercoms, Systems of sound of TV and other applications.

lm386 audio amplifier circuit diagram schematic

The power supply for this circuit should be 3 to 12 volts.

Suggestion of printed circuit board PCB

Printed Circuit Board, Pcb Component Silk, Pcb For Lm386 — Printed Circuit Board, Pcb Component Silk

Printed Circuit Board, Pcb Component View, Pcb For Lm386 — Printed Circuit Board, Pcb Component View.

Part List for the LM386 Amp

Part	Value
Resistors 1/4W 5%
R1	10 — Brown, Black, Gold, Gold
R2	1.2k — Brown, Red, Red, Gold
R3	4.7K — Yellow, Violet, Red, Gold
R4	1.5K — Brown, Green, Red, Gold (Optional)
R5, R6	10K — Brown, Black, Orange, Gold
Capacitors
C1, C6	10µF/16V — Electrolytic capacitor
C2	220µF/16V — Electrolytic capacitor
C3	100n — Ceramic or polyester capacitor
C4	1000µF/16V — Electrolytic capacitor
C5	100n — Ceramic Capacitor
Semiconductor
IC1	LM386n – DIP8 audio amplifier IC
Connectors
J2	P2 connector – audio input.
J1	Jack Connector – DC Power
CN1	Audio input connector (optional)
CN2	Power connector (Optional)
JP1	Gain adjustment jumper (optional)
LED1	Red LED 5 mm (Optional)
CN3	Terminal block 2 pin 5.08 mm
Miscellaneous
P1	Simple Potentiometer 4.7K to 10K
4.5 to 12V /1A power supply
PCB, solder, wires, Box, knob, etc.

Last update: 04/08/2021 16:34

Download the circuit PCB in PDF, PNG and Gerber
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If you liked this one, then check out the new version, stereo and with power supply design.

Download LM386 datasheet PDF

About the author

Toni

Xtronic.org blog author. Electronics technician for the technical school of Brasilia - Brazil. Interested in electronics, circuits and technology in general.