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LM2596S DC-DC Step-Down Power Supply Module
LM2596S DC-DC Step-Down Power Supply Module
Adjustable Buck Converter with SMD LED Indicator
Introduction
🔌
LM2596 Voltage Calculator
4.5V-40V Input → 1.25V-35V Output
4.5V-40V
Typical: 1kΩ
Variable
Output Voltage
3.75
Volts
Valid Range
Calculation Formula
Vout = 1.25V × (1 + R2/R1)
⚡ Must be ≤ Input Voltage
🔧 Range: 1.25V - 35V
The LM2596S is a step-down switching regulator capable of driving up to 3A load current with excellent line and load regulation. This module converts higher DC voltages to lower voltages with high efficiency (up to 92%).
Key Features
High Efficiency
Up to 92% conversion efficiency
Wide Input Range
4.5V to 40V input voltage
Adjustable Output
1.25V to 35V output (adjustable version)
LED Indicator
SMD LED for power indication
Technical Specifications
| Input Voltage | 4.5V – 40V DC |
|---|---|
| Output Voltage | 1.25V – 35V (adjustable), or fixed 3.3V, 5V, 12V |
| Output Current | 3A (max), 2A recommended for continuous operation |
| Conversion Efficiency | Up to 92% (depends on voltage difference) |
| Switching Frequency | 150kHz |
| Operating Temperature | -40°C to +125°C |
Pin Configuration
| Terminal | Label | Description |
|---|---|---|
| 1 | IN+ | Positive input voltage (4.5-40V) |
| 2 | IN- | Negative input/Ground |
| 3 | OUT+ | Positive output voltage |
| 4 | OUT- | Negative output/Ground |
| 5 | ADJ | Voltage adjustment (adjustable version only) |
Basic Connections
Note: For adjustable version, connect a multimeter to output terminals before powering on to verify voltage
Output Voltage Adjustment
|
1 2 3 4 5 6 7 8 9 |
// For adjustable version: // 1. Connect input power (4.5-40V) // 2. Use a small screwdriver to turn the blue potentiometer // 3. Measure output voltage with multimeter // 4. Adjust until desired voltage is reached // // Formula for output voltage: // Vout = 1.23V × (1 + R2/R1) // Where R2 is the variable resistor (potentiometer) |
Advanced Features
Input Protection
|
1 2 3 4 |
// Recommended protection: // - Add 100μF electrolytic capacitor at input // - Add reverse polarity protection diode // - Add fuse for high current applications |
Heat Management
|
1 2 3 4 |
// For high current applications: // - Add heatsink to LM2596 chip // - Ensure proper ventilation // - Derate current at high temperature |
Fixed Voltage Modules
|
1 2 3 4 5 |
// Fixed voltage versions available: // - LM2596S-3.3 (3.3V output) // - LM2596S-5.0 (5V output) // - LM2596S-12 (12V output) // No adjustment needed for fixed versions |
Efficiency Optimization
|
1 2 3 4 5 |
// For best efficiency: // - Keep input voltage close to output // - Use low ESR capacitors // - Keep traces short and wide // - Operate below 2A for continuous use |
Troubleshooting
No Output Voltage
- Check input power connection
- Verify input voltage is above 4.5V
- Check for short circuits on output
Unstable Output
- Add bulk capacitors (100-470μF) at input
- Add 10-100μF capacitor at output
- Check for proper grounding
Overheating
- Reduce load current below 2A
- Improve ventilation or add heatsink
- Check for short circuits
