LM317 Data Sheet – Adjustable Voltage Regulator – Unisonic

Part Number: LM317


Package: TO-220, TO-263, TO-252, TO-3, SOT-223 Type

Manufacturer: Unisonic Technologies


LM317 datasheet



The UTC LM317 is an adjustable 3-terminal positive voltage regulator, designed to supply 1A of output current with voltage adjustable from 1.3V ~ 37V.

This is a three-terminal positive voltage regulator integrated circuit that is commonly used in electronic circuits to provide a variable output voltage.


1. Output voltage adjustable from 1.3V ~ 37V

2. Output current in excess of 1A

3. Internal short circuit protection.

4. Internal over temperature protection.

5. Output transistor safe area compensation


Frequently Asked Questions Regarding the LM317

Q: Can the LM317 be used as a current regulator?
A: Yes, the LM317 can be used as a current regulator by connecting a resistor in series with the load and adjusting the output voltage such that the desired current flows through the load. The current flowing through the load can be calculated using Ohm’s law: I = V/R.

Q: What are some common applications of the LM317?
A: The LM317 is commonly used in power supply circuits, battery charger circuits, and voltage regulator circuits. It is also used in audio amplifier circuits and as a current regulator in LED driver circuits.

Q: Can the LM317 be used with a negative input voltage?
A: No, the LM317 is designed to work with positive input voltages only. To use the LM317 with a negative input voltage, a negative voltage regulator such as the LM337 can be used instead.

Q: How do I dissipate heat when using the LM317?
A: The LM317 can generate significant amounts of heat when regulating high currents or when there is a large difference between the input and output voltages. To dissipate heat, a heatsink can be attached to the LM317, or a fan can be used to blow air over the LM317. It is important to ensure that the maximum junction temperature of the LM317 (typically 125°C) is not exceeded.

LM317 Datasheet PDF Download

LM317 pdf

Other data sheets are available within the file:

LM317AA3-R, LM317T30Y, LM317TA3-T, LM317TF3T

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