An IMPORTANT NOTICE at the end of this data sheet addresses availability, warranty, changes, use in safety-critical applications, intellectual property matters . LM, LM Datasheet. DS – Rev 20 – May For further information contact your local STMicroelectronics sales office. The LM, LM are monolithic integrated circuits in TO, TOFP and DĀ²PAK packages intended for use as positive adjustable voltage regulators.

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Looking from the front of the voltage regulator, the first pin on the left is the Adjustable Pin, the middle is Vout, and the last pin on the right dagasheet V IN.

Retrieved 31 March The output current is that resulting from dropping the reference voltage across the resistor.

Product is in volume production. The alternative is to use a switching voltage regulator which is usually more efficient but has a larger footprint and requires a larger number of associated components. This page was last edited on 6 Julyat Linear regulators inherently waste power, the power dissipated is the current passed multiplied by the voltage difference between input and output. To feed a circuit the regulated 5 volts, we just connect it to the output pin.

They do not and cannot create voltage on their own. Menu Products Explore our product portfolio. It has many application circuits in its datasheet, but this IC is known for being used as a variable voltage regulator.

Accidenti come scotta questo transistor.

LM Voltage Regulator Pinout, Features, Equivalent & Datasheet

This is the trade-off for using linear regulators which are datasheeet simple way to provide a stable voltage with few additional components.

Linear integrated circuits Voltage regulation. The device can be configured to regulate the current to a load, rather than the voltage, by replacing the low-side resistor of the divider with the load itself.


C1 is optional and it’s used to clean up transient response. By using this site, you agree to the Terms of Use l3171 Privacy Policy. You can adjust it to any voltage within the range pm3171 the voltage regulator supports. In other projects Wikimedia Commons. LM Schematic Diagram Now that you know the pins, how do we modify the voltage to that which we want output?

In this circuit, we want a regulated 5VDC as output.

LM3171 Datasheet PDF – Fairchild Semiconductor

If you need to calculate output voltages or which resistor R2 value you would need for a circuit, see our LM Resistor and Voltage Calculator. The LM is a popular adjustable positive linear voltage regulator.

Please contact our sales support for information on specific devices. Generally, with regulators, unless they are low drop out regulators, you want the pm3171 voltage to be about 2 volts higher.

LM Datasheet PDF – Positive Voltage Regulator – Fairchild

Who We Are Management. V IN – V IN is the pin which receives the incoming voltage which is to be regulated down to a specified voltage. 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. We do this by changing the value of the resistor connected to the Adj pin of the voltage regulator.

Getting started with eDesignSuite 5: Archived from the original PDF on 18 April Because some quiescent current flows from the adjustment pin of the device, an error term is added:. For example, the LM may receive 12V as the input and output a constant 10V as output.

Now to make it act as a variable lm317 regulator we have to set variable voltages at pin 1 which can be done by using a potentiometer in the potential divider. Retrieved from ” https: Because of this, the error term in the formula cannot be ignored and the value of the low-side resistor becomes more critical. How to use LM No availability reported, please contact our Sales office.


This is the advantage dataheet adjustable voltage regulators. Key Features Output voltage range: Like the LM, each of the 78xx regulators is designed to adjust the output voltage until it is some fixed voltage above the adjustment pin which in this case is labelled ” ground “.

Marketing proposal for customer feedback. Support Center Video Center. The same formulae can also be used to calculate the value of resistor for you required output voltage. To adjust output, we swap out resistor R2 value for a different resistance. LM Datasheet The datasheet for datzsheet LM goes much more depth than this article, which was only created to serve as a beginner’s guide to this voltage regulator.

They are designed to supply more than 1. Therefore, you can see based on this formula, that the more the value of resistor R2 increases, the greater the voltage output. In our circuit, a motor is connected as a load which consumes around mA you can connect any load up to 1. Higher regulated voltages are obtained by connecting the adjustment pin to a resistive voltage divider between the output and ground.

In packages with a heat-dissipating mounting tab, such as TOthe tab is connected internally to the output pin which may make it necessary to electrically isolate the tab or the heat sink from other parts of the application circuit.

We’re going to put 12 volts into the voltage regulator and regulate it down to 5V.