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LM340T5 Voltage Regulator

The LM340T5 is a monolithic 3-terminal positive voltage regulator that employs internal current-limiting, thermal shutdown, and safe-area compensation, making them essentially indestructible. If adequate heat sinking is provided, they can deliver over 1.0A output current. Though it's mostly used as a fixed voltage regulator but tweaking it with some additional components these devices can be used with external components to obtain adjustable output voltages and currents.


LM340T5 Pinout Configuration

Pin Number

Pin Name



Input (V+)

Unregulated Input Voltage


Ground (GND)

Connected to Ground


Output (Vo)

Regulated Output Voltage


Features and Specifications

  • Complete specifications at 1A load
  • Output voltage tolerances of ±2% at Tj = 25˚C and ±4% over the temperature range
  • Line regulation of 0.01% of VOUT/V of ∆VIN at 1A load
  • Load regulation of 0.3% of VOUT/A
  • Internal thermal overload protection
  • Internal short-circuit current limit
  • Output transistor safe area protection
  • P+ Product Enhancement tested


Note: Complete technical details can be found in the LM340T5 datasheet given at the end of this page.


Other Voltage Regulators

LM7806, LM7809, LM7812, LM317, LM7905, LM7912, LM117V33, XC6206P332MR.


Available Packages

  • TO-3 Metal Can Package
  • TO-263 Surface-Mount Package
  • TO-220 Power Package
  • 3-Lead SOT-223 Package


How to use LM340T5 Voltage Regulator IC

Voltage regulators are one of the most commonly used components in any electronic circuit. They provide a constant output voltage or they can be used to step down the higher voltage to lower voltage. In our case the LM340T5 IC is an iconic regulator IC that finds its application in most of the projects and it is available in much different constant voltage configurations. The output current of this IC can go up to 1A. But as this IC is a linear regulator IC, it has to dissipate a lot of heat in order to work properly. As the IC suffers from heavy heat loss hence a heat sink is recommended for projects that consume more current. For example, if the input voltage is 12V and you are consuming 1A, then (12-5) * 1 = 7W. These 7 Watts will be dissipated as heat. And therefore, you need a large heat sink in order to dissipate that amount of power as a west heat.

Different Types of Voltage Regulators

By adding some external components in a proper configuration, this IC can be configured in many different applications and some of which are Fixed Voltage Regulator, Adjustable Voltage Regulator, and Constant Current Regulator.



  • Constant +5V output regulator to power microcontrollers and sensors in most of the projects
  • Adjustable Output Regulator
  • Current Limiter for certain applications
  • Regulated Dual Supply
  • Output Polarity-Reversal-Protection Circuit


2D Model and Dimensions

If you are looking to include this IC for your next PCB project, this 2D model of the device will come in handy.

LM340T5 Voltage Regulator Dimensions

Component Datasheet

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