LM386 SMD – SOIC-8 (Low Voltage Audio Power Amplifier)

Description

🔊 LM386 – Low Voltage Audio Power Amplifier (SMD Version)

📌 General Description

The LM386 is a low-power audio amplifier designed for use in low-voltage consumer applications. It requires few external components, operates on a single power supply, and can drive speakers or headphones directly — great for portable audio or DIY sound projects.

In SMD format, it’s often found in an 8-pin SOIC (Surface Mount) package, commonly labeled as LM386M-1, LM386M-3, or LM386M-4 depending on the gain version.

⚙️ Key Specifications

📦 SMD Package Info – SOIC-8

🧪 Features

• Operates on a single supply
• Needs very few external components
• Drives small speakers directly
• Gain adjustable from 20 to 200
• Works great with batteries (4–9V)

🔊 Typical Applications

• Mini audio amplifiers
• Voice output systems
• Radios and intercoms
• Portable audio devices
• Audio toys and beepers
• DIY guitar practice amps 🎸

📐 Example Circuit (Gain = 200)

           +V (5–12V)
              │
             .-.
             | | 10Ω
             | |
             '-'
              │
    Input -->─┬───┬─── Pin 3 (non-inv)
              │   |
             10k  0.047µF (Input cap)
              │   |
            GND  GND

    Gain Cap: 10µF between pins 1 & 8
    Output: Pin 5 → Speaker (with 220µF cap in series)

✅ Pros

• Extremely easy to use
• Available in both through-hole and SMD
• Works with low voltages (e.g., 5V from USB)
• Excellent for quick audio projects

⚠️ Design Tips

• Use a bypass cap (e.g. 10µF) between Pin 7 and GND to reduce noise
• Add a decoupling cap (e.g. 100nF) close to the VCC pin
• Speaker capacitor (usually 220µF–470µF) is essential to block DC from speaker