Adjustable voltage regulator LM317 Pinout and Other Details:
LM317 is a very famous adjustable voltage regulator IC available in many different packages. Today we are going to discuss about LM317 pinout, equivalent, uses, features and other details about this IC.
Technical Specifications:
1. Capable of providing upto 1.5A current at the output.
2. Voltage adjustable from 1.2V to 37V.
3. Requires low external components.
4. Requires only two external resistors for output adjustment.
5. Capable of short circuit protection.
6. Over heat shutdown function.
7. Low price.
8. Reliable to use in commercial applications.
9. Maximum input voltage is 40V DC.
10. Low standby current.

LM317 Description:
Previously we have discussed some fixed voltage regulator ICs like LM7805, LM7806, LM7809, LM7812 and LM7815. All these ICs are designed to provide a fixed output voltage.
LM317 is a widely used adjustable positive voltage regulator IC available in many different packages. The main reason for its wide usage is because it contains entire adjustable regulated power supply circuitry in a single chip due to which one can easily make a low cost and reliable adjustable power supply of 1.2V to 37V DC output voltage with upto 1.5A output current capability and very low external components.

Application Circuit:
The output is adjustable from 1.2V to 37V DC with max output current of 1.5A. The output voltage can be adjusted with the help of 5K variable resistor. The 40V input is not mandatory you can provide any voltage between 3V to 40V DC, depends on your output voltage requirements. For example if you want to build a 1.2V to 12V adjustable power supply then provide 3V higher than your maximum output voltage. In the above requirement of 1.2V to 12V supply the input voltage must not less than 15V.

1. Voltage step down circuits.
2. Lab power supplies.
3. Battery Chargers.
4. Solar Power Supplies.
5. Microcontroller Related Applications.
6. DC to DC converters.
7. Portable Instruments.

Replacement and Equivalent:
LM117, LM217, LM1086-ADJ, LT1086-ADJ, LT1117-ADJ, B29150, LM338, LM1084-ADJ. Some ICs may have different pin configuration from LM317, therefore check pin configuration before using in a circuit.

How to Safely Long Run in a Circuit:
To get stable and long term performance from LM317 do not provide input voltage more than 40V DC, do not drive load of more than 1.5A always use a proper heatsink.

Video Tutorial:

About the Author


Hello! My Dear Friends. I am Subramanian. I am writing posts on androiderode about Electronics testing and equipments.

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