LM317 Adjustable Voltage Regulator IC

The LM317 is a three-terminal adjustable positive voltage regulator IC capable of providing an output voltage from 1.25V to 37V with an output current of up to 1.5A. It is widely used in adjustable power supplies, battery chargers, LED drivers, voltage regulators, Arduino projects, and DIY electronics. The LM317 includes built-in current limiting, thermal overload protection, and safe operating area protection, making it a reliable choice for power regulation applications.

Features

• Full Name: LM317 Adjustable Positive Voltage Regulator
• Adjustable output voltage from 1.25V to 37V
• Output current up to 1.5A
• Built-in thermal overload protection
• Short-circuit current limiting
• Safe operating area (SOA) protection
• Excellent line and load regulation
• Requires only two external resistors to set output voltage

Specifications

Pin Configuration

Note: When viewing the front of the TO-220 package (text facing you, pins downward), the pin order is Adjust – Output – Input from left to right.

Applications

• Adjustable DC power supplies
• Battery chargers
• LED driver circuits
• Arduino and ESP32 power regulation
• Variable voltage power supplies
• Laboratory power supplies
• DIY electronics projects
• Industrial control systems

Advantages

• Wide adjustable output voltage range
• High output current capability
• Built-in protection features
• Excellent voltage regulation
• Easy to use with minimal external components
• Reliable and cost-effective
• Widely available

Size

Package Includes

• 1 × LM317 Adjustable Voltage Regulator IC

Note: The output voltage is determined by two external resistors using the formula: Vout = 1.25 × (1 + R2/R1). For applications with high output current or a large input-to-output voltage difference, use a suitable heatsink to prevent overheating and ensure reliable operation.