Part Number: LM317LZ/NOPB

Manufacturer: Texas Instruments

Description: IC REG LIN POS ADJ 100MA TO92-3

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LM317LZ/NOPB Description

The LM317L-N is a positive voltage regulator with an output voltage range that can be changed from 1.2 V to 37 V. It can supply 100 mA of current.With just two external resistors, the output voltage of the LM317L-N can be easily changed, making it a great choice for beginners.When compared to conventional fixed regulators, these models improve line and load regulation. The LM317L-N can be purchased in the industry-standard TO-92 transistor package, making it more convenient than ever to implement. The LM317L-N is fully protected against overloads. The current limit, safe area protection, and thermal overload protection are all built into the chip. In most cases, an input bypass capacitor is unnecessary, but if your device is located more than 6 inches from the input filter capacitors, you’ll need one.

The LM317L-N can be used to regulate many hundred-volt supplies because it has a floating topology and only checks the difference in voltage between the input and output.When a fixed resistor is put between the LM317L-adjustment N’s and its output, it can work as a precision current regulator, an adjustable switching regulator, or a programmable output regulator.You can get the LM317L-N in either a 3-pin TO-92, an 8-pin SOIC, or a 6-pin DSBGA. The LM317L-N is usable in temperatures ranging from -40 to +125 degrees Fahrenheit.

LM317LZ/NOPB Features

  • Variable output is lower than 1.2 V.
  • Output current of 100 mA.
  • able to handle voltages of up to 40 VIN.
  • Normally, line regulation is 0.01% /V.
  • Normally, load regulation is 0.1% A.
  • Not Needed an Output Capacitor ().
  • Constant with the temperature current limit.
  • reduces the need to stock a variety of voltages.
  • 3-Lead Transistor Packaging as Standard
  • Offered in 3-pin TO-92, 8-pin SOIC, or 6-pin.
  • package DSBGA.
  • Output is protected from short circuits.

LM317LZ/NOPB Feature Description

● Load Regulation

Even though the LM317L-N may be a very good load regulator, some safety measures are needed to make sure it works at its best.  It is necessary to tie the 240-amp set resistors—typically linked between the adjustment terminal and the output terminal—directly to the regulator’s output rather than close to the load. As a result, line drops are prevented from appearing in succession with the reference and deteriorating regulation. A 15-V regulator, for instance, will have a load regulation due to line resistance of 0.05 IL with a 0.05-resistance between the regulator and load. The effective line resistance will be 0.05 (1 + R2/R1), or 11.5 times worse, if the set resistor is connected close to the load.

Device Functional Modes

The Use of Capacitors on the Outside If the regulator is more than 6 inches from the typical big filter capacitor, a bypass capacitor at the input is advised. The input bypassing requirements of nearly all applications can be met by using either a 0.1-F disc or a 1-F solid tantalum. When adjustment or output capacitors are employed, the device becomes more sensitive to input bypassing not being there; however, the aforementioned values will ensure that no issues arise. In order to enhance ripple rejection and noise rejection, the LM317L-adjustment N’s terminal can be bypassed to ground. The output voltage can be increased without amplification of ripple and noise thanks to this bypass capacitor.

With a 10-F bypass capacitor, you can get 80 dB of ripple rejection at any output level.Increases of more than 10 F don’t make a big difference in how well ripples are blocked at frequencies over 120 Hz.Certain devices require protection diodes when using a bypass capacitor to prevent the capacitor from discharging over internal low current channels. Solid tantalum capacitors are the gold standard for use in electronic devices. Even at high frequencies, the impedance of solid tantalum capacitors is minimal. Depending on how the capacitor is made, a 1-F solid tantalum capacitor can be equivalent to around 25 F of aluminum electrolytic at very high frequencies. While ceramic capacitors are similarly effective at high frequencies, some varieties experience a drastic drop in capacitance at roughly 0.5 MHz.

Because of this, a 0.01-F disc may appear to function as a bypass better than a 0.1-F disc. The LM317L-N does not require any output capacitors to maintain stability; but, like with any feedback circuit, high levels of ringing can be induced by a circuit with a particular value of external capacitance. When the value is between 500 pF and 5000 pF, this phenomenon takes place. A solid tantalum capacitor of 1 F (or an electrolytic capacitor of 25 F of aluminum) connected to the output will cancel out this fluctuation and guarantee reliability.

● Protection Diodes

Protection diodes must be used from time to time when working with any IC regulator and external capacitors to keep the capacitors from discharging at low current points.Most 10-F capacitors have a low enough series resistance that, when they are shorted, they can cause 20-A spikes.The surge only lasts a short time, but it has enough power to stop the IC from working.

If the input is shorted and the regulator’s output capacitor is connected, the capacitor will drain into the regulator’s output.The rate of decrease of VIN, the output voltage of the regulator, and the value of the capacitor all affect the discharge current.In the LM317L-N, this discharge channel goes through a large junction that can easily handle a 2-A surge.However, this is not the case with all positive regulators. The LM317L-output N’s configuration and ballast resistors keep the peak current low enough that a protection diode isn’t necessary for output capacitors less than 25 F.

● DSBGA Light Sensitivity

The VREF of the LM317L-N DSBGA package may degrade if it is exposed to strong light. Fluorescent illumination in the workplace has little effect on productivity. Exposure to light does not permanently damage the LM317 DSBGA. When the LED is turned off, the LM317L-VREF N’s returns to its nominal value.


In conclusion, the LM317L-N is a very flexible positive voltage regulator that can be changed to offer many advantages over fixed regulators.There are only two external resistors needed to set the output voltage of this regulator, which can supply up to 100 mA over a wide 1.2 V to 37 V output range. As long as the maximum input-to-output difference is not exceeded, the regulator’s floating architecture allows it to handle hundreds of volts in supply voltage. There is current limit protection, thermal overload prevention, and safe area protection included in the gadget.

It can be used as a simple programmable output regulator or a precision current regulator. While capacitors are not required for stable operation, input bypass capacitors are recommended if the regulator is located more than 6 inches from the input filter capacitors. Additionally, protection diodes may need to be added to the device to prevent damage when using external capacitors. If you’re interested in purchasing the LM317L-N or other components for your project, ICRFQ is a trusted supplier with high-quality products and top-notch customer service.

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