The LM386 is a power amplifier designed for use in low-voltage consumer applications. To minimize external part count, the gain is internally set to 20, 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. It is remarkably efficient, making it the go-to chip for battery-powered devices such as portable AM-FM radios, small guitar amplifiers, and intercoms.
LM386 Pinout (DIP-8)
The LM386 comes in an 8-pin DIP package. The notch indicates the top of the IC for proper orientation.
| Pin | Terminal | Function |
| 1 | Gain | Set gain with an external capacitor/resistor |
| 2 | Input (–) | Inverting audio input |
| 3 | Input (+) | Non-inverting audio input |
| 4 | Ground (GND) | Negative supply connection |
| 5 | Output | Amplified audio signal to speaker |
| 6 | VS | Positive supply voltage |
| 7 | Bypass | Decoupling point for the internal power supply |
| 8 | Gain | Combined with Pin 1 to increase gain |
Technical Specifications
- Supply Voltage (VS): 4V to 12V (Standard) / 5V to 18V (LM386N-4)
- Quiescent Current: 4mA
- Voltage Gain: 20 to 200 (Adjustable)
- Output Power: 125mW to 1W (Depending on variant/load)
- Input Resistance: 50 kΩ
- Distortion (THD): 0.2% (Typical)
Key Features & Benefits
- Low Battery Drain: High efficiency ensures long life in portable projects.
- Minimal External Parts: Requires very few capacitors to create a working amplifier.
- Wide Supply Range: Works perfectly on a standard 9V battery or 5V USB power.
- Self-Biasing: The output automatically centers at half-supply for maximum signal swing.
Common Applications
- Portable Radios: Powering speakers in small AM/FM receivers.
- Guitar Practice Amps: Used in famous “Crackerbox” or “Ruby” amp designs.
- TV Sound Systems: Providing audio for low-power consumer monitors.
- Ultrasonic Drivers: Driving transducers in cleaning or range-finding gear.
LM386 Equivalent & Substitutes
- NJM386 (Direct equivalent from JRC)
- LM380 (Higher power audio amp alternative)
- TDA2822 (Dual-channel low power alternative)
- MC34119 (Low voltage speakerphone amplifier)
Related Tutorials on ElxHub
- Basics: Learn more in Integrated Circuits – Basics and Working
- Selection Guide: Compare power options in our Ultimate IC Selection Guide
Conclusion
The LM386 is the undisputed king of DIY audio. Its simplicity and forgiving nature make it the perfect “first amplifier” for students and hobbyists. Despite its age, its ability to produce clear sound from a single low-voltage battery ensures its place as a staple in the world of audio electronics.
Download the IC’s Datasheet pdf
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