LM2596 Switching Voltage Regulator (Buck Converter) — Datasheet, Pinout & Circuit
The LM2596 is a step-down switching regulator (buck) from Texas Instruments. The LM2596 is a high-efficiency step-down switching voltage regulator capable of handling up to 3A of output current. It offers higher efficiency than traditional linear regulators.
What is the LM2596?
The LM2596 is a Step-down switching regulator (Buck) from the LM259x series by Texas Instruments. Primary applications:
- Efficient power supplies
- Battery systems
- Automotive applications
- Portable devices
- DC-DC converters
- Industrial power systems
Key Specifications
- Output Voltage: 1.23V - 37V (adjustable)
- Maximum Current: 3A
- Type: Step-down switching regulator (Buck)
- Package: TO-220/TO-263
Datasheet and Pinout
Pin configuration of LM2596 regulator in TO-220-5 package
| Pin | Name | Function |
|---|---|---|
| 1 | VIN | Input voltage (4.5V-40V) |
| 2 | ON/OFF | On/Off control |
| 3 | GND | Ground |
| 4 | FB | Feedback |
| 5 | SW | Switch output |
📄 Official Datasheet: Download PDF
Technical Specifications
| Parameter | Value |
|---|---|
| Output Voltage | 1.23V - 37V (adjustable) |
| Maximum Current | 3A |
| Regulator Type | Switching |
| Package | TO-220/TO-263 |
| Manufacturer | Texas Instruments | | operating Voltage | 4.5V - 40V (input) | | max Current | 3A | | temperature | -40°C to +125°C | | package Type | TO-220-5, TO-263-5 | | frequency | 150kHz fixed | | efficiency | Up to 92% | | ripple Rejection | N/A (switching) |
Typical Circuit
The LM2596 requires minimal external components. The basic circuit includes:
- Input capacitor (C1): 0.1 µF – 1 µF (ceramic or electrolytic) between VIN and GND — filters input noise.
- Output capacitor (C2): 1 µF – 10 µF (electrolytic) between VOUT and GND — stabilizes output and improves transient response.
- Resistor network R1/R2: Sets the output voltage. VOUT = VREF × (1 + R2/R1) + IADJ × R2.
⚠️ Always add a heatsink if current exceeds 500mA or if the Vin – Vout difference is greater than 3V. Power dissipated: P = (Vin – Vout) × Iload.
Variants and Alternatives
| Component | Vout | Imax | Type |
|---|---|---|---|
| LM2596S | — | — | Alternative |
| LM2596HV | — | — | Alternative |
| MP1584 | — | — | Alternative |
Applications with Arduino and DIY Projects
The LM2596 is ideal for projects requiring a clean, regulated supply:
- Power Arduino from 12V: Converts to 1.23V - 37V (adjustable) for the Arduino VIN pin.
- Breadboard prototypes: Minimal circuit (IC + 2 capacitors) fits any breadboard.
- Audio projects: Adjustable voltage for preamps and audio stages.
- Sensors and modules: Clean supply for DHT11, ultrasonic sensors, etc.
Frequently Asked Questions (FAQ)
What is the LM2596 used for? It is a Step-down switching regulator (Buck) that converts a higher input voltage into a stable 1.23V - 37V (adjustable) output. The LM2596 is a high-efficiency step-down switching voltage regulator capable of handling up to 3A of output current. It offers higher efficiency than traditional linear regulators.
How much current can the LM2596 supply? Up to 3A continuously with an adequate heatsink. Without a heatsink, limit to 100–200 mA to prevent overheating.
Does the LM2596 need a heatsink? Yes, when power dissipation P = (Vin – Vout) × I exceeds ~1W. For light loads (under 200 mA) with a small voltage difference, it can operate without a heatsink.
What is the difference between LM2596 and its alternatives? The LM2596S is a direct pin-compatible alternative. The main difference is usually the manufacturer (TI, Fairchild, ST) and slight variations in datasheet specifications.
Where can I buy the LM2596? At local electronics stores, eBay, Mouser, DigiKey, or AliExpress. For prototyping, breakout modules that include the IC with capacitors already mounted are also available.
What is the LM2596 pinout? See the pinout table above. For the TO-220/TO-263 package: with the flat side facing you and pins pointing down, the pin order is shown left to right in the table. Download the official datasheet for the complete diagram.