TL431: Overview,parameter,Main uses,Features,application fields,working principle and alternative models


TL431 Voltage Reference Overview:


The TL431 is a programmable precision shunt regulator integrated circuit commonly used in various electronic circuits for voltage regulation and control purposes.


  • Reference Voltage: The output reference voltage of the device.
  • Cathode Current: Maximum current drawn from the device.
  • Operating Temperature Range: Range within which the device operates reliably.
  • Package Type: Physical package of the IC.
  • Adjustable Threshold: Ability to set the reference voltage.

Main Uses:

  • Voltage Regulation: Provides stable reference voltage for control circuits.
  • Feedback Control: Used in feedback circuits for controlling power supplies.
  • Comparators: Employed as a voltage reference in comparator circuits.
  • Protection Circuits: Utilized in overvoltage protection circuits.


  • Adjustable Output: Reference voltage can be programmed.
  • Low Output Noise: Provides a stable and noise-free reference voltage.
  • Low Dropout Voltage: Minimal voltage loss across the device.
  • High Accuracy: Precision output voltage for accurate regulation.
  • Wide Operating Voltage Range: Suitable for diverse voltage applications.

Application Fields:

  • Switching Power Supplies: Voltage reference and feedback control.
  • Battery Charging Circuits: Voltage regulation in battery chargers.
  • Voltage Monitors: Used as a reference in voltage monitoring circuits.
  • Automotive Electronics: Voltage regulation in automotive systems.

Working Principle:

  • Comparative Amplifier: Compares the reference voltage with the input voltage.
  • Error Amplifier: Generates an error signal based on the comparison.
  • Comparator: Determines if the input voltage is above or below the reference.
  • Output Control: Adjusts the output to maintain the desired reference voltage.

Alternative Models:

  • LM431: Alternative precision adjustable shunt regulator from Texas Instruments.
  • KA431: Comparable shunt regulator IC from Fairchild Semiconductor.
  • REF02: Voltage reference IC with fixed output voltage.

The TL431 is a versatile voltage reference IC widely used for voltage regulation and control in various electronic applications. Alternative models like the LM431 or KA431 offer similar functionality with slight variations in features and specifications. Engineers choose specific models based on requirements such as accuracy, voltage range, and package options for optimal performance in their designs. Detailed datasheets and specifications help in selecting the most suitable voltage reference IC for specific circuit requirements.