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:

• 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

Part List for the LM386 Amp

Last update: 04/08/2021 16:34

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Download LM386 datasheet PDF