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LM386–Low Voltage Audio Power Amplifier

The LM386M-1 and LM386MX-1 are power amplifiers 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 mW when operating from a 6-V supply, making the LM386M-1 and LM386MX-1 ideal for battery operation.

What is LM386 IC

The LM386 is a mono low voltage amplifier that can be used in a variety of applications. It can drive loads from 4 Ω to 32 Ω. The gain is internally set to 20 but it can be modified from 20 to 200 by placing a resistor and capacitor between pins 1 and 8. This device comes in three different 8-pin packages as PDIP, SOIC and VSSOP to fit in different applications.

LM386 datasheet

LM386 Features

  • Battery Operation
  • Minimum External Parts
  • Wide Supply Voltage Range: 4 V–12 V or 5 V–18 V
  • Low Quiescent Current Drain: 4 mA
  • Voltage Gains from 20 to 200
  • Ground-Referenced Input
  • Self-Centering Output Quiescent Voltage
  • Low Distortion: 0.2% (AV = 20, VS = 6 V, RL = 8 Ω, PO = 125 mW, f = 1 kHz)
  • Available in 8-Pin MSOP Package

LM386 Applications

  • AM-FM Radio Amplifiers
  • Portable Tape Player Amplifiers
  • Intercoms
  • TV Sound Systems
  • Line Drivers
  • Ultrasonic Drivers
  • Small Servo Drivers
  • Power Converters

LM386 Equiplent


LM386 Pinout and Pin Configuration

LM386 has 7 pins and their name and descriptions is as the following table.

Pin NumberPin NameDescription
1,8GAINUsed to set the gain of the IC by connecting to a Capacitor
2Inverting Input (IN-)The Inverting Pin of amplifier is normally grounded
3Non-Inverting Input (IN+)The Non-Inverting pin is provided with the audio signal
4GroundThe ground pin is connected to the ground of the system
5VoutProvides amplified audio output, connected to speaker
6Vss/VccConnected to power
7BypassBypass pin is used for connecting a decoupling capacitor
lm386 pinout
lm386 pinout

How does the lm386 work

LM386 schematic

LM386 schematic
LM386 schematic

The LM386 just requires several capacitors and resistors to begin working. A very fundamental ordinarily utilized LM386 circuit is demonstrated as follows.

The IC is fueled utilizing the stick 6 (regularly 5 or 9V) and the ground stick 4 is associated with the ground. The modifying pin (stick 2) is typically grounded and the Non-altering pin (stick 3) is given the Audio signal. This sound sign can be from a receiver or even from a 3.5mm jack. The 10k resistor is included arrangement with the sound sign to go about as a volume control. You can overlook this potentiometer in the event that you need to work in full volume.

The stick 1 and stick 8 are utilized to set the increase of the Amplifier. In the event that there is nothing associated between these pins, at that point the default addition will be 26 dB, yet we can interface a 10 uF capacitor crosswise over it to get the greatest ain of the IC which is 46dB. The stick 7 is utilized to interface a separating capacitor (0.1uf) for our intensifier IC to keep away from pointless motions. The enhanced sound sign can be acquired from the stick 5 which is associated with a 8-ohm speaker through a sifting capacitor. The RC coordinate with 0.05uF and 10k resistor is discretionary.


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