LM317S/NOPB Series

series introduction

# LM317S/NOPB Product Series Introduction

## 1. Overview
The LM317S/NOPB is a highly versatile and widely used adjustable three - terminal positive voltage regulator from Texas Instruments. This product series is designed to provide a stable and adjustable output voltage, making it an essential component in a vast array of electronic circuits and power supply applications.

## 2. Key Features

### 2.1 Adjustable Output Voltage
One of the most significant features of the LM317S/NOPB is its ability to provide an adjustable output voltage. It can be set anywhere from 1.2V to 37V, which gives designers great flexibility in meeting the specific voltage requirements of different electronic devices. This adjustability is achieved through the use of two external resistors, allowing for easy customization of the output voltage according to the application's needs.

### 2.2 High Output Current
The LM317S/NOPB can deliver a relatively high output current of up to 1.5A. This makes it suitable for powering a wide range of loads, from small - scale integrated circuits to larger power - hungry components. Whether it's powering a microcontroller, an amplifier, or other electronic modules, the LM317S/NOPB can provide the necessary current to ensure proper operation.

### 2.3 Low Dropout Voltage
The device has a low dropout voltage, which means that it can maintain a stable output voltage even when the input - to - output voltage differential is relatively small. This is particularly important in battery - powered applications, where conserving battery life is crucial. A low dropout voltage allows the regulator to operate efficiently over a wider range of input voltages, reducing power dissipation and extending the battery's runtime.

### 2.4 Thermal Overload Protection
To ensure the reliability and safety of the device, the LM317S/NOPB is equipped with thermal overload protection. If the device's temperature rises above a certain threshold due to excessive power dissipation, the thermal protection circuitry will automatically reduce the output current or shut down the regulator to prevent damage. This feature helps to prevent overheating and extends the lifespan of the component.

### 2.5 Short - Circuit Protection
Another important safety feature is short - circuit protection. In the event of a short circuit at the output, the LM317S/NOPB will limit the output current to a safe level, protecting both the regulator and the connected load from damage. This feature adds an extra layer of reliability to the power supply system.

## 3. Package and Pin Configuration

### 3.1 Package Type
The LM317S/NOPB is available in a TO - 220 package. The TO - 220 package is a popular choice for power - handling components due to its excellent thermal performance and ease of mounting on a heat sink. It provides good mechanical stability and is suitable for both through - hole PCB assembly, making it compatible with a wide range of manufacturing processes.

### 3.2 Pin Configuration
- **Input Pin (Pin 1)**: This pin is connected to the unregulated input voltage source. The input voltage should be higher than the desired output voltage by at least the dropout voltage of the regulator.
- **Adjust Pin (Pin 2)**: The adjust pin is used to set the output voltage. By connecting two external resistors between the output and the adjust pin, and between the adjust pin and ground, the output voltage can be precisely adjusted according to the formula \(V_{OUT}=1.25V(1 + \frac{R_2}{R_1})\), where \(R_1\) is the resistor connected between the output and the adjust pin, and \(R_2\) is the resistor connected between the adjust pin and ground.
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Images for reference

TO-263-3, TS3B

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Datasheets

Partlist

LM317S/NOPB