LM386 Low Voltage Audio Power Amplifier
The LM386 is a low-voltage audio power amplifier. It is designed for use in consumer audio applications. The gain is internally set to 20. Gain can be increased up to 200 with external components. A minimum number of external parts are required.
It operates with voltages from 4 V to 12 V. Output power is suitable for driving small speakers. Quiescent current draw stays low. Built-in gain and input biasing simplify usage. Output automatically centers around half the supply voltage.
This IC fits battery-powered audio devices. It supports hobbyist and compact audio projects. It enables amplification of microphones, signals, or audio playback in space-limited systems. Heat dissipation stays low under typical loads.
Applications
Audio amplifiers in portable electronics
Voice output in communication systems
Alarm and buzzer sound generation
Small speaker driver for toys or gadgets
Signal amplification in hobby audio systems
Audio output in radios and intercoms
DIY music and effects circuits
Sound effects modules
Microphone preamps for embedded systems
Audio playback for low-power applications
Key Features
Low-voltage operation: 4 V to 12 V
20 internal voltage gain (up to 200 configurable)
Drives 8 Ω speakers with up to 700 mW output
Minimal external parts required
Low quiescent power draw: 4 mA typical
Built-in gain and biasing
Voltage gain adjustable via pins 1 and 8
Output bias set to half supply voltage
Low harmonic and crossover distortion
Available in DIP-8 and SOIC-8 packages
Pin Configuration (8-Pin DIP/SOIC)
| Pin | Name | Description |
|---|---|---|
| 1 | Gain | Gain setting (use with Pin 8) |
| 2 | Inverting Input | Audio input signal |
| 3 | Non-inv. Input | Ground or reference voltage |
| 4 | GND | Ground |
| 5 | Output | Audio output |
| 6 | V+ | Supply voltage |
| 7 | Bypass | Optional bypass capacitor |
| 8 | Gain | Gain setting (use with Pin 1) |
Specifications Table
| Parameter | Value |
|---|---|
| Supply Voltage Range | 4 V to 12 V |
| Output Power (8 Ω load) | 325 mW at 6 V, 700 mW at 9 V |
| Voltage Gain (Default) | 20 (26 dB) |
| Voltage Gain (Max) | 200 (46 dB) with external caps |
| Total Harmonic Distortion | ≤ 0.2% ‘ |
| Slew Rate | 0.2 V/µs |
| Quiescent Current | 4 mA typical |
| Bandwidth | 300 kHz |
| Output Impedance | Low (suitable for 8 Ω speakers) |
| Operating Temperature Range | 0 °C to +70 °C |
| Package Types | DIP-8, SOIC-8 |
