TL431AIDBZR Shunt Regulator Replacements, Working Principle, Typical Characteristics, Performance and Function

02 February 2024

Ⅰ. Description of TL431AIDBZR

Ⅱ. How does TL431AIDBZR work?

Ⅲ. Typical characteristics of TL431AIDBZR

Ⅳ. Performance of TL431AIDBZR

Ⅴ. Specifications of TL431AIDBZR

Ⅵ. How to adjust the output voltage of TL431AIDBZR?

Ⅶ. Absolute maximum ratings of TL431AIDBZR

Ⅷ. What is the function of TL431AIDBZR?

Ⅸ. Where is TL431AIDBZR used?

TL431AIDBZR is a three-terminal voltage regulator widely used in power management and voltage reference circuits. In this article, we will provide a comprehensive overview of the TL431AIDBZR, delving into its characteristics, specifications, performance, and application fields. Our aim is to enhance your understanding and facilitate the effective application of this chip.

Ⅰ. Description of TL431AIDBZR


The TL431AIDBZR is a precision programmable reference, which belongs to the TL431 series. It employs an adjustable precision reference voltage source and a comparator to control the output voltage by adjusting an adjustable resistor to achieve stable control of the output voltage. The regulator has a wide operating voltage range of 2.5V to 36V, making it suitable for a wide range of power management applications. It is available in a SOT-23-3 package, making it ideal for miniaturized designs. In addition, the chip has an output current capability of 100mA, which provides sufficient current for circuits.

The TL431AIDBZR has a typical output impedance of only 0.2 Ω. Its active output circuit has excellent conduction characteristics, which makes this device an ideal replacement for Zener diodes in many applications such as on-board regulation, adjustable power supplies and switching power supplies. It is available in B, A and standard grades with initial tolerances (at 25°C) of 0.5 percent, 1 percent and 2 percent, respectively. In addition, its low output drift relative to temperature ensures device stability over the entire temperature range.

Replacements and equivalents:







Ⅱ. How does TL431AIDBZR work?

The internal circuitry of the TL431AIDBZR contains a comparator, a reference voltage source, an error amplifier, and an output driver. These components work together to maintain a stable voltage on the reference pin. The TL431AIDBZR incorporates a feedback control loop centered around comparing the voltage disparity between the reference pin and an internal reference voltage, usually set at 2.5 V. The internal circuitry responds to this variance by adjusting the output drivers to uphold the reference voltage at the predetermined level. The internal circuitry of the TL431AIDBZR begins to operate when current is supplied between pin 2 (anode) and pin 1 (cathode). This current is divided through an external resistor to produce a voltage that is compared to the internal reference voltage. If the external divider voltage is higher than 2.5V, the comparator senses the difference and adjusts the output driver to reduce the voltage on the reference pin. Conversely, if the external divider voltage is below 2.5V, the comparator will increase the output voltage so that the reference pin voltage increases.

Ⅲ. Typical characteristics of TL431AIDBZR

Data at high and low temperature are applicable only within the recommended operating free-air temperature ranges of the various devices.


Ⅳ. Performance of TL431AIDBZR

• Low noise: The noise level of TL431AIDBZR is very low, making it suitable for noise-sensitive applications.

• High accuracy: The output voltage accuracy of TL431AIDBZR can reach 0.5 percent, which is higher accuracy than other three-terminal voltage regulators.

• High current output: The maximum output current of this voltage regulator can reach 100mA, which is suitable for some high-power power management applications.

• Low drift: The output voltage of this regulator exhibits minimal drift, and its output voltage remains stable even after temperature changes or long-term use.

Ⅴ. Specifications of TL431AIDBZR

• Its initial accuracy is 1 percent.

• Its installation method is SMD or SMT.

• Its temperature coefficient is 92PPM/°C.

• The manufacturer of TL431AIDBZR is Texas Instruments.

• The length of TL431AIDBZR is 2.92 mm, the width is 1.3 mm, and the height is 1 mm.

• TL431AIDBZR has 3 pins and is available in a SOT-23-3 package and a tape and reel packaging.

• The voltage reference circuit has a minimum operating temperature of -40°C and a maximum operating temperature of 85°C.

Ⅵ. How to adjust the output voltage of TL431AIDBZR?

To regulate the output voltage of TL431AIDBZR, it is necessary to modify the resistances of both R1 and R2. The process involves initially establishing a value for either R1 or R2, followed by employing a designated formula to calculate the resistance value for the remaining resistor. Note that whichever calculation method is used, we must make sure that the voltage at pin R is 2.5 V. That is, if we assume that the output voltage is X, then the output voltage divider on R2 (if it is in the circuit) should be equal to the reference voltage of the TL431, 2.5 V. The formula is: (R2/R1+R2)*X=2.5v, where X represents the output voltage. If the output voltage X is known, then we can use this formula to calculate the resistance of R1 or R2. If the resistance value of one resistor is known, then we can also use the formula to calculate the resistance value of the other resistor.

Ⅶ. Absolute maximum ratings of TL431AIDBZR

Over operating free-air temperature range (unless otherwise noted)


1. Exceeding the specified limits in Absolute Maximum Ratings could result in irreversible damage to the device. It's important to note that these ratings solely represent stress limits, and using the device under these conditions or any others not outlined in the recommended operating conditions is not suggested for normal functionality. Exposure to absolute-maximum-rated conditions for extended periods may affect device reliability.

2. All voltage values are with respect to ANODE, unless otherwise noted.

Ⅷ. What is the function of TL431AIDBZR?

The TL431AIDBZR can be used for a variety of applications with external components. For example, it can be used as a constant-current source by connecting a PNP transistor and a current-limiting resistor to the chip for use in current control circuits. The regulator can also be used in overcurrent protection circuits. When the current in the circuit exceeds a certain threshold, the chip drops its output voltage, thereby triggering other protection circuits. In addition, the voltage regulator can be used in a temperature measurement circuit. By connecting it to temperature sensors and other components, high-precision temperature measurement and control can be realized.

Ⅸ. Where is TL431AIDBZR used?

The TL431AIDBZR is widely used in areas such as secondary-side voltage regulation in flyback switched-mode power supplies (SMPS), voltage monitoring, adjustable voltage and current references, zener diode replacements, and comparators with integrated references.

The TL431AIDBZR is widely used for secondary-side voltage regulation in flyback switched-mode power supplies (SMPS). Thanks to its efficient and stable performance, it can provide a stable voltage output on the secondary side of the power supply, ensuring the stability and reliability of the power supply.

In the field of voltage monitoring, the TL431AIDBZR can be used to monitor the voltage in a circuit and pass the monitoring results to the control system or processor. This allows the system to be adjusted and controlled accordingly based on the real-time monitored voltage values.

The regulator demonstrates excellent performance in the field of adjustable voltage and current references. It is capable of providing stable voltage and current outputs that can be precisely adjusted by external resistors. This makes it ideal for applications requiring precise voltage and current control.

In addition, the regulator can be used as a Zener diode replacement. Zener diodes are a commonly used regulator device, but their performance is affected by temperature and other factors. On the contrary, the TL431AIDBZR provides enhanced stability and a reduced footprint, positioning it as a perfect substitute for Zener diodes.

Finally, the TL431AIDBZR can also be used as a comparator with an integrated reference. Comparators are a common electronic component used to compare the magnitude of two input signals, and the TL431AIDBZR has a built-in reference voltage that can be used as a reference source for the comparator, simplifying circuit design and improving performance stability.

Frequently Asked Questions

1. What are the three 3 basic types of voltage regulators?

There are three types of Switching voltage regulators: Step up, Step down, and Inverter voltage regulators.

2. What is the replacement and equivalent of TL431AIDBZR?

You can replace the TL431AIDBZR with LM431SBCMFX, TL431ACDBZR, TL431-AE2-R, TL431AQDBZR, TL431AQDBZRQ1 or TL431IDBZR.

3. What are the pin functions of TL431AIDBZR?

TL431AIDBZR usually has three pins: Cathode (cathode), Anode (anode) and Reference (reference). By connecting these pins, the operating mode of the TL431AIDBZR can be configured.

4. What is TL431AIDBZR?

The TL431AIDBZR is an adjustable precision voltage reference commonly used in power management and voltage regulation circuits. It can be configured as a voltage regulator or used as a voltage comparator.