The LM LM are adjustable 3-terminal negative volt- age regulators capable of supplying in excess of b1 5A over an output voltage range of b1 2V to . The LM/LM are adjustable 3-terminal negative volt- .. Reproduction of TI information in TI data books or data sheets is permissible only if reproduction. LM/LMN 3-Terminal Adjustable Negative Regulators. Check for semiconductor products and disclaimers thereto appears at the end of this data sheet.

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For large voltage datasueet, the energy lost as heat can ultimately be greater than that provided to the circuit. The LM is designed to compensate for these fluctuations internally, making such measures unnecessary. This is the trade-off for using linear regulators which are a simple way to provide a stable voltage with few additional components.

LM137 Datasheet

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. The LM is a popular adjustable positive linear voltage regulator. Linear regulators inherently waste power, the power dissipated is the current passed multiplied by the voltage difference between input and output. Accidenti come scotta questo transistor.


The LM is an adjustable analogue to the popular 78xx fixed regulators. The LM relates in the same way to the fixed 79xx regulators. The output current is that resulting from dropping the reference voltage across the resistor.

LM datasheet, Pinout ,application circuits LM – Negative Adjustable Regulator

The LM negative complement to the LM regulates voltages below, rather than above, the reference. Archived from the original on 17 December Because of this, the error term in the formula cannot be ignored and the value of the low-side resistor becomes more critical.

Wikimedia Commons has media related to LM and Voltage regulator circuits.

Views Read Edit View history. 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. Archived from the original PDF on 18 April From Wikipedia, the free encyclopedia.

Archived from the original PDF on 31 March 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. It was designed by Robert “Bob” Pease.

Retrieved 31 March In other projects Wikimedia Commons. Retrieved from ” https: 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 “.


Higher regulated voltages are obtained by connecting the adjustment pin to a resistive voltage divider between the output and ground. By using this site, you agree to the Terms of Datasheeet and Privacy Policy.

This page was last edited dtasheet 6 Julyat Failure to do this may cause the circuit to short. The LM has three pins: Linear integrated circuits Voltage regulation. Because some quiescent current flows from the adjustment pin of the device, an error term is added:. However, the 78xx device’s quiescent current is substantially higher and less stable.

How the adjustment pin is connected determines the output voltage as follows.

National Semiconductor

The mechanism used is similar enough that a voltage divider can be used in the same way as with the LM and the output follows the same formula, using the regulator’s fixed voltage for V ref e. If the adjustment pin is connected to ground the output pin delivers a regulated voltage of 1.

In use an LM commonly requires a heat sink to prevent the operating temperature rising dataasheet high.