## LM386G-S08-R: Low Voltage Audio Power Amplifier The **LM386G-S08-R** is a specific variant of the widely used LM386 integrated circuit. It is an audio power amplifier designed for use in low-voltage consumer applications. The suffixes in the part number typically denote the package type and packaging method (Tape & Reel). --- ### 1. Key Technical Specifications | Parameter | Specification | | :--- | :--- | | **Supply Voltage (Vs)** | 4V to 12V (standard version) | | **Quiescent Power Drain** | 24mW (at 6V supply) | | **Voltage Gain** | 20 to 200 (adjustable via external cap) | | **Package Type** | SOP-8 (Surface Mount) | | **Output Power** | ~325mW (at Vs=6V, Load=8Ω) | | **Distortion (THD)** | 0.2% (typical) | --- ### 2. Pin Configuration (SOP-8) The device features 8 pins, each serving a specific role in the amplification process: 1. **Gain (Pin 1):** Used to adjust the gain with Pin 8. 2. **Inverting Input (Pin 2):** Usually connected to ground in single-ended applications. 3. **Non-Inverting Input (Pin 3):** The audio signal input. 4. **GND (Pin 4):** System ground. 5. **Vout (Pin 5):** The amplified audio output. 6. **Vs (Pin 6):** Positive power supply voltage. 7. **Bypass (Pin 7):** Decoupling path for internal bias (reduces noise). 8. **Gain (Pin 8):** Used with Pin 1 to set gain between 20 and 200. --- ### 3. Internal Design & Features * **Self-Biasing:** The inputs are ground-referenced, while the output is automatically biased to one-half the supply voltage. * **Low Current Drain:** Its low quiescent current makes it ideal for battery-operated devices (like portable radios or hand-held games). * **Adjustable Gain:** By leaving Pins 1 and 8 open, the internal resistor sets the gain to **20**. Placing a capacitor between Pins 1 and 8 increases the gain to **200**. --- ### 4. Common Application Circuit To build a basic amplifier using the LM386G-S08-R, the following external components are typically required: ```mermaid graph LR Input --> C1(Input Capacitor) C1 --> Pin3(LM386 Pin 3) Pin6(VCC) --> C2(Bypass Cap) Pin5(Output) --> C3(Coupling Cap) C3 --> Speaker ``` * **10µF Capacitor (Pins 1 & 8):** Sets maximum gain. * **250µF Capacitor (Pin 5):** Blocks DC from reaching the speaker. * **0.05µF + 10Ω Resistor (Pin 5 to GND):** A "Zobel Network" to prevent high-frequency oscillation. --- ### 5. Part Number Suffix Breakdown * **LM386:** Base part number (Audio Amplifier). * **G:** Often denotes "Green" or Halogen-Free materials. * **S08:** Indicates the **SOP-8** (Small Outline Package) surface mount footprint. * **R:** Indicates **Tape & Reel** packaging for automated assembly. ---