TL431AIDBZR
Three-terminal adjustable shunt regulator with 2.5V to 36V output range, 0.5% precision, and wide operating current for power supply and voltage reference applications.
Product Overview
Description
The TL431AIDBZR is a programmable precision shunt regulator that functions as an adjustable Zener diode with excellent temperature stability.
It can be programmed to any voltage from 2.5V to 36V using two external resistors, with 0.5% initial accuracy and low temperature coefficient.
The device operates with cathode currents from 1mA to 100mA, making it suitable for a wide range of applications including power supply feedback, voltage monitoring, and precision references.
Product Series
Primary Application
Key Features
- Adjustable output: 2.5V to 36V
- 0.5% initial accuracy (A grade)
- Low temperature coefficient: 20ppm/°C
- Wide operating current: 1mA to 100mA
- Low output impedance
- Short-circuit protected
Specifications
| Reference Voltage | 2.5V (Vref) |
|---|---|
| Output Voltage Range | 2.5V to 36V |
| Initial Accuracy | 0.5% (A grade) |
| Temperature Coefficient | 20 ppm/°C (typ) |
| Cathode Current Range | 1mA to 100mA |
| Package | SOT-23-3 |
| Voltage Rating | N/A |
| Current Rating | N/A |
| Temperature Range | -40°C to +85°C |
Applications
Power supply feedback
Industrial application for Adjustable Precision Shunt Regulator
Voltage monitoring
Industrial application for Adjustable Precision Shunt Regulator
Precision voltage reference
Industrial application for Adjustable Precision Shunt Regulator
Constant current sources
Industrial application for Adjustable Precision Shunt Regulator
Isolated power supply regulation
Industrial application for Adjustable Precision Shunt Regulator
FAE Expert Insights
"The TL431 is one of the most versatile components in analog design. It's essentially a programmable Zener diode with excellent precision and temperature stability. I use it constantly in power supply designs for feedback regulation - it's the standard reference in most isolated flyback and forward converters. The 0.5% accuracy is sufficient for most applications, and the wide operating range makes it flexible. The SOT-23 package is compact and easy to place. Key design tip: the reference input current (2-4μA) affects the resistor divider accuracy, so use low-value resistors (typically 10kΩ range) for best precision. This device has been around forever because it just works reliably."
Versatile precision shunt regulator for power supply applications
— Maria Garcia, BeiLuo
Frequently Asked Questions
How do I calculate resistor values for TL431?
The TL431 output voltage is set by Vout = Vref × (1 + R1/R2), where Vref = 2.5V. For example, for 5V output: R1/R2 = (5/2.5) - 1 = 1. Use R2 = 10kΩ, R1 = 10kΩ. Consider reference input current (2-4μA) when using high-value resistors. For best accuracy, use 1% tolerance resistors and keep divider current >100× reference current.
Use low-value resistors (10kΩ range) for best accuracy. Verify with calculation.
What is the difference between TL431A and TL431C?
The TL431A offers 0.5% initial accuracy while TL431C offers 1% accuracy. Both have same temperature coefficient and electrical characteristics. Choose A grade for higher precision applications (power supplies requiring tight regulation) and C grade for general applications where 1% is sufficient. The price difference is typically 10-20%.
Use A grade for precision power supplies. C grade is sufficient for most applications.