Linear regulators inherently waste power; the power dissipated is the current passed multiplied by the voltage difference between input and output. A LM commonly requires a heat sink to prevent the operating temperature from rising too high. For large voltage differences, the power lost as heat can ultimately be greater than that provided to the circuit. This is the tradeoff for using linear regulators, which are a simple way to provide a stable voltage with few additional components. 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.
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They are exceptionally easy to use and require only two external resistors to set the output voltage. Further, both line and load regulation are better than standard fixed regulators.
Also, the LM is packaged in standard transistor packages which are easily mounted and handled. Included on the chip are current limit, thermal overload protection and safe area protection.
All overload protection circuitry remains fully functional even if the adjustment ter- minal is disconnected. Normally, no capacitors are needed unless the device is situated more than 6 inches from the input filter capacitors in which case an input bypass is needed.
An optional output capacitor can be added to improve transient response. The adjustment terminal can be bypassed to achieve very high ripple rejection ratios which are difficult to achieve with stan- dard 3-terminal regulators. Besides replacing fixed regulators, the LM is useful in a wide variety of other applications.
Also, it makes an especially simple adjustable switching regulator, a programmable output regulator, or by connecting a fixed resistor between the adjustment pin and output, the LM can be used as a precision current regulator.
Sup- plies with electronic shutdown can be achieved by clamping the adjustment terminal to ground which programs the out- put to 1.
For the negative complement, see LM series data sheet.
LM317AT DATASHEET PDF
The LM series of adjustable 3-terminal positive voltage regulators is capable of supplying in excess of 1. They are exceptionally easy to use and require only two external resistors to set the output volt- age. Further, both line and load regulation are better than standard fixed regulators. Also, the LM is packaged in standard transistor packages which are easily mounted and handled. Included on the chip are current limit, thermal overload protection and safe area protection.
Zolomuro Full output current not available at high input-output voltages. This is the trade-off for using linear regulators which are a simple way to provide a stable voltage with few additional components. LM can be used as a precision current regulator. The LM is a popular adjustable positive linear voltage regulator. Pmat, no capacitors are needed unless the device is sit. LMAT datasheet and lmta datasheet Download datasheet. The LM negative complement to the LM regulates voltages below, rather than above, the reference.
LM317AT National Semiconductor, LM317AT Datasheet
Datasheet Texas Instruments LM317AT