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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Failure to do this may cause the circuit to short. In use an LM commonly requires a heat sink to prevent the operating temperature rising too high.
LM Datasheet(PDF) – National Semiconductor (TI)
Archived from the original PDF on 18 April It was designed by Robert “Bob” Pease. 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.
The LM relates in the same way to the fixed 79xx regulators.
However, the 78xx device’s quiescent current is substantially higher and less stable. Higher regulated voltages are obtained by connecting the adjustment pin to a resistive voltage divider between the output and ground.
How the xatasheet pin is connected determines the output voltage as follows.
Because of this, the error term in the formula cannot be ignored and the value of the low-side resistor becomes more critical. Accidenti come scotta questo transistor. The output current is that resulting from dropping the reference voltage across the resistor. The LM is a popular adjustable positive linear voltage regulator. This is the trade-off for using linear regulators which are a simple way to provide a stable voltage with few additional 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.
LM datasheet, Pinout ,application circuits LM – Negative Adjustable Regulator
Archived from the original on 17 December 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
The alternative is to datashheet a switching voltage regulator which is usually more efficient but has a larger footprint and requires a larger llm137 of associated components. 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. The LM has three pins: The LM negative complement to the LM regulates voltages below, rather than above, the reference.
If the adjustment pin is connected to ground the output pin delivers a regulated voltage of 1. Wikimedia Commons has media related to LM and Voltage regulator circuits. Archived from the original PDF on 31 March The LM is designed to compensate for these fluctuations internally, making such measures unnecessary. The LM is an adjustable analogue to the popular 78xx fixed regulators. In other projects Wikimedia Commons. Like the LM, each of the 78xx regulators is designed to adjust eatasheet output voltage until it is some fixed voltage above the adjustment pin which in this case is labelled ” ground “.
Linear dtaasheet circuits Voltage regulation.
Views Read Edit View history. Because some quiescent current flows from the adjustment pin of the device, an error term is added:.