LM317 PDF Datasheet – Adjustable Voltage Regulator

This post explains for the regulator. A voltage regulator is an electronic device that is used to maintain a constant voltage level, regardless of changes in load or input voltage.

It does this by adjusting the output voltage so that it remains within a specified range.

This helps to ensure that the voltage supplied to a device remains within the acceptable range, even under varying conditions such as changes in temperature or load.

The Part Number is LM317.

The function of this semiconductor is 3-Terminal Adjustable Regulator.

The package is TO-220, TO-92 Type

Manufacturer: Wing Shing Computer Components

Preview images :

LM317 pdf pinout datasheet

What is LM317?

The LM317 are adjustable 3-terminal positive-voltage regulators capable of supplying 1.5A over a differential voltage range of 3V to 40V. They are exceptionally easy to use and require only two external resistors to set the output voltage. Both input and output regulation is better than standard fixed regulators.

In addition to higher performance than fixed regulators, these regulators offer full overload protection available only in integrated circuits. Included on the chip are current limit, thermal overload protection, and safe-area protection. All overload protection circuit remains fully functional even if the adjustment terminal is disconnected. Normally, no capacitors are needed unless the device is situated far from the input filter capacitors in which case an input bypass is needed.

The LM317 can handle a wide range of input voltages, up to 40 volts, and can provide output voltages ranging from 1.2 volts to 37 volts with a maximum current of 1.5 amps. It has built-in protection features such as thermal shutdown and current limiting to prevent damage to the device and the circuit it is connected to.

This device is commonly used in power supply circuits, battery charging circuits, and voltage regulation applications where a stable and adjustable output voltage is required. It is also used in audio amplifiers, signal generators, and other electronic devices.


1. Output Voltage Range Adjustable from 1.2 V to 37V

2. Output Current Capability of 1.5A Max

3. Input Regulation Typically 0.01% Per Input-Volt Change

4. Output Regulation Typically 0.1%

5. Peak Output Current Constant over Temperature Range of Regulator


Absolute Maximum Ratings (Ta = 25°C)

1. Input-Output Voltage Differential VI – VO : 40V

2. Operating Junction Temperature Range : 0℃ to +125℃

3. Continuous total dissipation at 25℃ free-air temperature : 2000mW

4. Continuous total dissipation at (or below ) 25℃ case temperature : 15W

5. Storage Temperature : –65℃ to +150℃

6. Lead Temperature1.6 mm from case for 10 seconds : 260℃


Other data sheets are available within the file: LM317T, LM317LZ

LM317 PDF Datasheet