LM317 pinout | Introduction | Configuration | Features | Advantages | Application

As we know that IC is available in various forms like 555 timers, single logic gates, microcontroller, microprocessor, voltage regulator, and op-amps like different ICs. IC  LM741, LM324 IC, LM339 IC, LM117, LM358, LM7805, LM138, and many more ICs are available. Here we have to learn or introduce IC LM37. Let us have a deep insight into the introduction, pinout, features, advantages, applications of LM317.

Introduction to LM317:

When it comes to variable control, the LM317 is almost certainly the best choice. It can be used as a fixed voltage regulator, current limiter, battery charger, AC voltage regulator, and even an adjustable current regulator in addition to being a variable voltage regulator. 

LM317 Pinout Diagram:

Pin 1: Adjust - This pin adjusts the output voltage.

Pin 2: Output voltage - The regulated output voltage set by the adjusted pin can be obtained from this

 Pin 3: Input voltage- The input voltage which has to be regulated is given to this pin

LM317 pinout

Features of LM317:

  • The output voltage can set to range from 1.25 to 37V
  • Adjustable 3 terminal positive voltage regulator
  • Require low external component
  • The maximum input to output voltage difference is 40V, recommended 15V
  • The maximum output current when a voltage difference is 15V is 2.2A
  • Available in to-220, SOT223, TO263 package
  • The output current is 1.5A.
  • Overheat shutdown function
  • Capable of short circuit protection
  • Require only two external resistors for output adjustment
  • Low price
  • Reliable to use in commercial applications
  • Low standby current
  • There are 80 dB ripple rejection
  • The operating junction temperature is 125 °C

Application of LM317:

  • Used for positive voltage regulation
  • Variable power supply
  • DC to Dc converter
  • Battery charger
  • Solar power supply
  • Microcontroller related application
  • Current limiting circuits
  • Used in motor control circuits
  • Reverse polarity circuit
  • Commonly used in desktop, PC, DVD, and other consumers products
  • Portable instruments

Simple application circuit of LM317:

The LM317 voltage regulator is demonstrated in this simple circuit. Only two external resistors are needed in this case. Capacitors may also be used to eliminate voltage differences at the input and output terminals. These capacitors help to reduce the output voltage ripple.

Simple application circuit of LM317

The output voltage of this circuit depends on resistors R1 and R2. The equations for calculating output voltage will be:

VOUT: 1.25 * ( 1+(R2+R1)
If R1 & R2 are minimum, the output will be equal to 1.25
If R1=R2, the output voltage will be 2.5 volts.

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