Description
LM386 Audio Amplifier IC
The LM386 is a low power audio frequency amplifier which is very commonly used in small audio amplifiers. The IC consumes very less power and hence can be operated using a 9V battery easily. It can easily drive an 8-ohm speaker with a variable gain of 20 to200. Volume control and gain control is also possible in this. The IC comes in an 8-pin PDIP package and requires very fewer components to function hence it is highly easy to use. ( find out a wide range of OP-AMP at solicstores.in).
So, if you are looking for an audio amplifier IC which can be powered using a battery for a portable application to drive an 8-ohm speaker then this IC might be the right choice for you. For driving heavy speakers you have to use the power amplifier ICs..
386 Pin Configuration
| Pin Number | Pin Name | Description |
| 1,8 | GAIN | Used to set the gain of the IC by connecting to a Capacitor |
| 2 | Inverting Input (IN-) | The Inverting Pin of the amplifier is normally grounded |
| 3 | Non-Inverting Input (IN+) | The Non-Inverting pin is provided with the audio signal |
| 4 | Ground | The ground pin is connected to the ground of the system |
| 5 | Vout | Provides amplified audio output, connected to a speaker |
| 6 | Vss/Vcc | Connected to power |
| 7 | Bypass | Bypass pin is used for connecting a decoupling capacitor |
How to use the LM386 IC
The LM386 only requires a couple of capacitors and resistors to start working. A very basic commonly used LM386 circuit is shown below.
The IC is powered using the pin 6 (typically 5 or 9V) and the ground pin 4 is connected to the ground. The inverting pin (pin 2) is normally grounded and the Non-inverting pin (pin 3) is provided with the audio signal. This audio signal can be from a microphone or even from a 3.5mm jack. The 10k resistor is added in series with the audio signal to act as a volume control. You can ignore this potentiometer if you want to operate in full volume.
The pin 1 and pin 8 are used to set the gain of the Amplifier. If there is nothing connected between these pins then the default gain will be 26 dB, but we can connect a 10 uF capacitor across it to get the maximum gain of the IC which is 46dB. The pin 7 is used to connect a filtering capacitor (0.1uf) for our amplifier IC to avoid unnecessary oscillations. The amplified audio signal can be obtained from pin 5 which is connected to an 8-ohm speaker through a filtering capacitor. The RC network with 0.05uF and 10k resistor is optional.
features and specifications
- Supply Voltage: 4-15V
- Quiescent Power: 24mW @ 6V
- Analog input voltage 0.4V (maximum)
- Voltage Gain: 20 to 200 (26dB to 46dB)
- PSRR: 50dB
- Speaker impedance 4Ω
- Available in 8-Pin PDIP, SOIC and VSSOP packages
Applications
- AM and FM Radio amplifiers
- Portable music players
- Low Power Audio amplifiers
- Wien bridge oscillator
- Power Amplifiers
- Audio boosters
Package Includes :
1 x LM386 Low Voltage Audio Amplifier IC
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