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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However, the 78xx device’s quiescent current is substantially higher and less stable. Views Read Edit View history. Linear integrated circuits Voltage regulation.

The LM relates in the same way to the fixed 79xx regulators. How the adjustment pin is connected determines the output voltage as follows. If the adjustment pin is connected to ground the output pin delivers a regulated voltage of 1. Because of this, the error term in the formula cannot be ignored and the value of the low-side resistor becomes more critical.

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. Archived from the original PDF on 31 March This is the trade-off for using linear regulators which are a simple way to provide a stable voltage with few additional components.


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

Higher regulated voltages are obtained by connecting the adjustment pin to a resistive voltage divider between the output and ground. 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.

LM137 – Negative Adjustable Regulator

It was designed by Robert “Bob” Pease. In use an LM commonly requires a heat sink to prevent the operating temperature rising too high. 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 “. Datasgeet other projects Wikimedia Commons.

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

Accidenti come scotta questo transistor. This page was last edited on 6 Julyat The LM has three pins: Retrieved 31 March Retrieved from ” https: The output current is that resulting from dropping the reference voltage across the resistor. The LM is designed to compensate for these fluctuations internally, making such measures unnecessary.

Archived from the original PDF on 18 April The LM negative complement to the LM regulates voltages below, rather than above, the reference. Because some quiescent current flows from the adjustment pin of the device, an error term is added:. 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. 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 LM is an adjustable analogue to the popular 78xx fixed regulators. Archived from the original on 17 December By using this site, you agree to the Terms of Use and Privacy Policy.

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.

Failure to do llm137 may cause the circuit to short. The LM is a popular adjustable positive linear voltage regulator.

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