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LM2940S 1A Low Dropout Voltage Regulator

The LM2940S is a positive voltage regulator that features the ability to source 1A of output current with a dropout voltage of typically 0.5V and a maximum of 1V over the entire temperature range along with a maximum input voltage of 26V.


LM2940S Pinout Configuration

Pin Number

Pin Name




Unregulated input voltage






Regulated output voltage.





Features and Specifications

  • Input Voltage Range = 6 V to 26 V
  • Dropout Voltage Typically 0.5 V at IOUT = 1 A
  • Output Current over 1 A
  • Output Voltage Trimmed Before Assembly
  • Reverse Battery Protection
  • Internal Short Circuit Current Limit
  • Mirror Image Insertion Protection
  • P + Product Enhancement Tested


Note: Complete technical details can be found in the LM2940S Datasheet given at the end of this page.


Alternative Low Dropout Regulators Like LM2940S

AP2112, MIC5205, BA3258HFP, RT9193


How to use LM2940S Low Dropout Regulator

The LM2940S is a versatile Low Dropout (LDO) Regulator and can be used for many applications, it is an IC that comes in compact packaging with 3 pins for input/output and ground pins. The circuit shown below is a typical application circuit of LM2940S IC. The circuit includes a power source, two capacitors, and the voltage regulator IC.

LM2940S IC Application Circuit Diagram

The circuit shown below is a typical application circuit of the LM2940S IC. The circuit includes a power source, two capacitors, and the LM2940S voltage regulator IC. As we can observe, when an input voltage of 9V is provided through the LM2940S IC, the output voltage we obtain is 5V DC. The image above represents all the internal circuit components of the regulator IC. The application circuit is shown above also consists of two ceramic capacitors. Ceramic capacitor C1(100uF) is used to deal with the problems of input impedance, whereas capacitor C2(1uF) is used to provide a stable output voltage. Ceramic capacitors are used here because they are faster than electrolytic capacitors.


Available Packages

TO-220, DDPAK/TO-236, WSON(NGN), SOT-223



Here are some of the applications of the LM2940S IC.

  1. Remote control cars
  2. Current Limiter for certain applications
  3. Regulated Dual Supply
  4. Phone chargers
  5. Power distribution circuits
  6. Post Regulator for Switching Supplies
  7. Logic Power Supplies
  8. Industrial Instrumentation


2D Model and Dimensions

Below is the 2D model of the voltage regulator IC along with its dimensions in inches(millimeters). The following information can be used to design the custom footprints and can be used for PCB designing and CAD modeling.

LM2940S Dimensions

Component Datasheet

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