The LM317 device is an adjustable three-terminal positive-voltage regulator capable of supplying more than 1.5 A over an output voltage range of 1.25 V to 37 V. It requires only two external resistors to set the output voltage. The device features a typical line regulation of 0.01% and a typical load regulation of 0.1%. It includes current limiting, thermal overload protection, and safe operating area protection. Overload protection remains functional even if the ADJUST terminal is disconnected.
Feature:-
- Adjustable 3-terminal positive voltage regulator
- The output voltage can be set to range from 1.25V to 37V
- Output current is 1.5A
- Maximum Input to output voltage difference is 40V, recommended 15V
- Maximum output current when the voltage difference is 15V is 2.2A
- Operating junction temperature is 125°C
Pin Configuration:-
| Pin Number | Pen Name | Description |
| 1 | Adjust | This pin adjusts the output voltage |
| 2 | Output Voltage (Vout) | The regulated output voltage set by the adjust pin can be obtained from this pin |
| 3 | Input Voltage (Vin) | The input voltage which has to be regulated is given to this pin |
Where to use LM317?
When it comes to variable voltage regulation requirements LM317 would most likely be the first choice. Apart from using it as a variable voltage regulator, it can also be used as a fixed voltage regulator, current limiter, Battery charger, AC voltage regulator and even as an adjustable current regulator. One notable drawback of this IC is that it has a voltage drop of about 2.5 across it during regulation, so if you looking to avoid that problem look into the other equivalent IC’s given above.
So, if you are looking for a variable voltage regulator to deliver current up to 1.5A then this regulator IC might be the right choice for your application.
How to use LM317?
LM317 is a 3-terminal regulator IC and it is very simple to use. It has many application circuits in its datasheet, but this IC is known for being used as a variable voltage regulator. So, let’s look into how to use this IC as a variable voltage regulator.
As said earlier the IC has 3 pins, in which the input voltage is supplied to pin3 (VIN) then using a pair of resistors (potential divider) we set a voltage at pin 1 (Adjust) which will decide the output voltage of the IC that is given out at pin 2 (VOUT). Now to make it act as a variable voltage regulator we have to set variable voltages at pin 1 which can be done by using a potentiometer in the potential divider. The below circuit is designed to take 12V (you can supply up to 24V) as input and regulate it from 1.25V to 10V.
Package Includes:-
- LM317 Voltage Regulated IC ( 10 PCS )
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Pavan Kushwaha (verified owner) –