5 December 2019

LM337 pinout | Introduction | Configuration | Application

Introduction to LM337 IC:

As we know that there are available in various forms of 555 timers, single logic gates, microcontroller, microprocessor, voltage regulator and op-amps like different ICs IC  LM741, LM324 IC, LM339 IC, LM358, LM338, LM337, and many more ICs are available. Here we have to learn or introduce about  IC LM337, it is an adjustable 3 terminal negative voltage regular capable of supplying in excess of 1.5A over an output voltage of -1.2V to -37V. The LM337  serves a wide variety of applications including local, on-card regulations. The LM337 is the equivalent counterpart of the LM317 positive voltage regular. The IC commonly used in adjustable lab voltage in combination with the LM317 IC. It can also be used as current as well as the negative voltage protection circuit.  Let us have a deep insight into the introduction, pinout configuration, features, packages, advantages, applications of LM337.

LM337 pin configuration:

Pin 1: Adjust - These pins adjust the output voltage.
Pin 2: Input voltage(Vin ) - The input voltage which hs to be regulated is given to this pin.
Pin 3: Output voltage(Vout) - The regulated output voltage set by the adjust pin can be obtained from this pin 

lm337 pinout

Features of LM337 pinout:

  • It is an adjustable 3 terminal negative voltage regulator.
  • Its output voltage can be set to range from -1.25V to 37V.
  • The operating junction temperature is 125 C.
  • output voltage adjustable down to VRFF.
  • 0.01%/V typical line regulation.
  • 0.3%/V typical load regulation.
  • The current limit is constant with temperature.
  • Ripple rejection around 77 dB.
  • Standard 3 lead transistor packages.
  • 9.50 ppm/°C temperature coefficient.
  • Excellent thermal regulation around 0.002%/V.
  • Maximum output current when voltage difference 15V is -2.2A.
  • Differential input and the output voltage is 40V, recommended 15V.
  • The maximum output current is -1.5A.
  • Available into To-220, SOT223, TO263 package.

LM337 voltage regulator descriptions:

The LM337 is the basically equivalent counterpart of the LM317 positive voltage regulator.  This IC is commonly used in adjustable lab voltage generators in combination with the LM317 IC. It can be also used in the current regulator. This IC is basically three PINs in which the input voltage supplied to Vin pin then using a pair of the register that we set a voltage at adjusting pin which will decide the output voltage of the IC that given out at Vout pin. The below circuit is shown for reference from the LM337 datasheet.

The output voltage thus obtained can be calculated using the below formula.

Vout  = -1.25 * (1 + (R2/R1))

The actual formula in the datasheet will also include current through the adjust a pin but for a simplification purpose, we have assumed Iadj to be 50uA constant which will slightly differ in the practical application. Also, note that the output current of the IC will not be 1.5A always if the difference voltage between the input and output voltage is high the output current will also decrease. 

Applications of  LM337:

  • Used for positive voltage regulations.
  • Variable power supply.
  • Current limiting circuits.
  • Used in motor control circuits.
  • Commonly used in desktop PC, DVDs, and other consumer products.
  • Reverse polarity circuits.

Conclusions :

Here this post gives the all about information of IC LM 337 like pinout, pin configurations, applications, advantages, features, and also real-life applications. We hope you all understand this topic. Furthermore, queries regarding your project please give your feedback by commenting in the comment sections.

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