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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National Semiconductor

Archived from the original PDF on 18 April In other projects Wikimedia Commons. Like the LM, each of the 78xx regulators is designed to lm173 the output voltage until it is some fixed voltage above the adjustment pin which in this case is labelled ” ground “.

The LM relates in the same way to the fixed 79xx regulators. The LM is designed to compensate for these fluctuations internally, making such measures unnecessary.

This page was last edited on 6 Julyat However, the 78xx device’s quiescent current is substantially higher and less stable. Because of this, the error term in the formula cannot be ignored and the value of the low-side resistor becomes more critical.

Linear integrated circuits Voltage regulation. By using this site, you agree to the Terms of Use and Privacy Policy.


The LM is a popular adjustable positive linear voltage regulator. The LM has three pins: Accidenti come scotta questo transistor. The LM negative complement to the LM datasheet voltages below, rather than above, the reference. If the adjustment pin is connected to ground the output pin delivers a regulated voltage of 1.

Views Read Edit View history. 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 datsheet fixed voltage for V ref e.

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

LM Datasheet PDF – Texas Instruments

l,137 Higher regulated voltages are obtained by connecting the adjustment pin to a resistive voltage divider between the output and ground. Retrieved from ” https: 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.

Archived from the original on 17 December Because some quiescent current datashfet from the adjustment pin of the device, an error term is added:.

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.


The output current is that resulting from dropping datashewt reference voltage across the resistor.

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

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. Linear regulators inherently waste power, the power dissipated is the current passed multiplied by the voltage difference between input and output.

For large voltage differences, the energy lost as heat can ultimately be greater than that provided to the circuit.

From Wikipedia, the free encyclopedia.

LM137 Datasheet PDF

Failure to do this may cause the circuit to short. Archived from the original PDF on 31 March It was designed by Robert “Bob” Pease. In use an LM commonly requires a heat sink to prevent the operating temperature rising too high. Retrieved 31 March Datashest Commons has media related to LM and Voltage regulator circuits. This is the trade-off for using linear regulators which are a simple way to provide a stable voltage with few additional components. The LM is an adjustable analogue to the popular 78xx fixed regulators.