Correct installation and use of TL431AIDBZ

By Texas Instruments 100

Correct installation and use of TL431AIDBZ

TL431AIDBZ is a voltage reference source, which belongs to the voltage regulator product series. This product is a three-terminal adjustable component with the advantages of high precision, high stability, and low cost. TL431AIDBZ is mainly used in various occasions, such as power management, voltage stabilization, voltage comparison, etc. The system can set the output voltage by an external resistor network, thereby achieving voltage control of other devices in the circuit.

TL431AIDBZT is an adjustable precision shunt voltage regulator, which belongs to the integrated circuit category in electronic components. It is a product of Texas Instruments and is a similar product to TL431, TL431A, TL431B, TL432, TL432A, TL432B and other models.

Ⅰ.Specification parameters of TL431AIDBZ

•Initial accuracy:1%
•Product type:Reference voltage
•Installation style:SMD/SMT
•Height:1 mm
•Width:1.3 mm
•Length:2.92 mm
•Output type:adjustable
•Maximum output voltage:36 V
•Minimum operating temperature:-40℃
•Maximum operating temperature:+125℃
•Temperature coefficient:92 PPM/C
•Output voltage:Adjustable
•Current-Cathode:700 µA
•Current-output:100 mA
•Shunt current—Max:100 mA
•Shunt current—minimum:600 uA
•Voltage-Output (maximum):36 V
•Topology:Shunt References
•Voltage-Output (minimum/fixed):2.495V
•Series VREF—Input Voltage—Max:36 V
•Subcategory:PMIC-Power Management ICs
•Reference type:Shunt Adjustable Precision References


Ⅱ.Characteristics of TL431AIDBZ

1.Small package: TL431AIDBZ usually adopts small package, such as TO-92, SOT-23, etc., which is suitable for small circuit board design.

2.Wide range of applications: Due to its excellent performance and stability, TL431AIDBZ is widely used in power management, voltage regulation, comparator and other circuits.

3.High precision: TL431AIDBZ has a high-precision reference voltage and can provide stable and accurate reference voltage output. This makes it important in circuits that require precise voltage control.

4.Low dynamic output impedance: It has low dynamic output impedance, which helps to improve the stability and dynamic response of the circuit.

5.Internal overvoltage protection: The internal protection circuit can prevent the output voltage from exceeding the set value, improving the safety of the circuit.

6.Wide operating voltage range: TL431AIDBZ is able to operate within a wide operating voltage range, usually 2.5V to 36V. This enables it to adapt to application needs in different voltage environments and improve the reliability and stability of the circuit.

7.Low cost: Due to its simple design and wide range of applications, TL431AIDBZ has low cost and is suitable for mass production and cost-sensitive applications.

8.Good stability: It can maintain stable output under various working conditions, with low temperature drift and long-term stability.

9.Low power consumption: TL431AIDBZ adopts low power consumption design and is suitable for battery-powered or low-power consumption applications. This gives it significant advantages in applications such as portable devices, sensors, and low-power circuits, and can effectively extend the working time of the device.

10.Low temperature drift: TL431AIDBZ has low temperature drift characteristics, allowing the output voltage to maintain stability under different temperature conditions. This feature allows it to maintain good working performance in high or low temperature environments and adapt to various complex environments.

11.Programmability: By adjusting the difference between the input voltage (Vin) and the reference voltage (Vref), the target value of the output voltage (Vout) can be programmed. This programmability allows the TL431AIDBZ to adapt to different application needs, allowing precise control of the output voltage through simple adjustments.

Ⅲ.Working principle of TL431AIDBZ

•The working principle of TL431AIDBZ is based on its internal circuit structure and function implementation. TL431AIDBZ is an adjustable precision shunt voltage regulator. Its core working principle is to stabilize the output voltage through internal comparators and amplifier circuits.

•The internal structure of TL431AIDBZ includes a 2.5V precision reference voltage source, a voltage comparator and an output switch tube. These components work together to stabilize and regulate the output voltage.

•When the voltage between the cathode (CATHODE) and anode (ANODE) of TL431AIDBZ exceeds the 2.5V reference voltage of the reference terminal (REF), the voltage comparator will output a high-level signal, causing the output switch to turn on. At this time, a low-impedance path is formed between the anode and the cathode, and the output voltage decreases until the voltage between the cathode and the anode is equal to 2.5V. In this way, TL431AIDBZ is able to maintain the stability of the output voltage.

•On the contrary, when the voltage between the cathode and the anode is lower than 2.5V, the voltage comparator outputs a low-level signal and the output switch is turned off. At this time, a high-impedance path is formed between the anode and cathode, and the output voltage increases. By adjusting the difference between the input voltage and the reference voltage, the target value of the output voltage can be changed to achieve programmability.

•TL431AIDBZ also has temperature compensation and internal bias circuits to reduce the impact of temperature on the output voltage and improve the stability of the circuit. In addition, its high input impedance and low input current characteristics enable it to provide good performance in circuits.


Ⅳ.Application fields of TL431AIDBZ

1.Power management: TL431AIDBZ can be used for voltage stabilization and voltage regulation functions in power management circuits. It can be used as a reference voltage source to provide a stable reference voltage for feedback control of the stability of the power supply output voltage.

•Voltage Stability: TL431AIDBZ can be used as a voltage stabilizer to provide a stable output voltage for the circuit. Its internal 2.5V reference voltage source can be used as a reference. Through the adjustment of the external circuit, the output voltage can be maintained at the set value and is not affected by input voltage fluctuations or load changes.

•Voltage Regulation: In applications requiring programmable output voltage, the TL431AIDBZ can change the output voltage by adjusting the voltage difference between its cathode and anode. This voltage adjustment function allows circuit designers to flexibly set the value of the output voltage according to actual needs.

•Feedback control: TL431AIDBZ is often used together with operational amplifiers to form a feedback control circuit. When the output voltage deviates from the set value, the operational amplifier will detect this deviation and correct the deviation by adjusting the cathode or anode voltage of TL431AIDBZ to return the output voltage to the set value, thereby ensuring the stability of the power supply output.

•Current Limitation: TL431AIDBZ can also be used in current limiting circuits. By detecting the size of the output current and adjusting the output voltage when necessary, overcurrent conditions in the circuit can be prevented and circuits and equipment are protected from damage.

2.LED driver: In LED lighting systems, TL431AIDBZ can be used in current regulator circuits to provide a stable reference current for driving LEDs and maintaining constant brightness.

3.Communication system: In communication systems, TL431AIDBZ is often used for power management and level control. It can provide stable power output for communication equipment while achieving precise control of levels to ensure communication quality and stability.

•Stable power output: By combining with appropriate external components (such as resistors and capacitors), TL431AIDBZ can produce a stable output voltage to provide reliable power for communication equipment.

•Linear adjustment: In many communication systems, linear adjustment is the key to ensuring output signal quality. The TL431AIDBZ provides an extremely linear voltage reference, ensuring that communication systems maintain linear performance over a wide dynamic range.

•Level control: In communication systems, precise control of signal levels is crucial to ensure signal quality and avoid distortion. The TL431AIDBZ can be used as a voltage reference to adjust the gain or attenuation of the signal level.

•Electromagnetic Compatibility (EMC): Power management of communications equipment is critical to reducing electromagnetic interference (EMI) and electromagnetic susceptibility (EMS). By using the TL431AIDBZ to stabilize power output, communication systems can reduce potential electromagnetic interference and improve overall electromagnetic compatibility.

4.Electronic measuring instruments: Among electronic measuring instruments, the high precision and stability of TL431AIDBZ make it an ideal voltage reference source. It can provide accurate reference voltage for measuring instruments and improve the accuracy and precision of measurements.

•Accurate reference voltage: Electronic measuring instruments, such as oscilloscopes, voltmeters, ammeters, etc., require accurate reference voltages to calibrate and compare measurement results. TL431AIDBZ can provide an extremely stable 2.5V reference voltage, providing an accurate benchmark for measuring instruments.

•Improve measurement accuracy: Due to the high-precision characteristics of TL431AIDBZ, it can help electronic measuring instruments reduce errors and improve measurement accuracy. This is critical for applications that require high-precision measurements, such as scientific research, engineering testing, quality control, etc.

5.Voltage controller: TL431AIDBZ can also be used as a voltage controller, such as a voltage regulator in a DC-DC converter to achieve precise control and regulation of the output voltage.

•Output voltage regulation: In the DC-DC converter, TL431AIDBZ is used as a reference voltage source, combined with the error amplifier, power switch and other control circuits, to achieve precise regulation of the output voltage. By adjusting the reference voltage of TL431AIDBZ, the desired output voltage value can be set.

•Current limiting and overvoltage protection: TL431AIDBZ can also be combined with appropriate circuits to implement current limiting and overvoltage protection functions. When the output voltage or current exceeds a predetermined value, the control signal of TL431AIDBZ can be adjusted to limit the current or turn off the power supply, thereby protecting the circuit and load from damage.

6.Switching power supply: In the switching power supply, TL431AIDBZ can be used as a voltage controller to adjust the output voltage by controlling the on-off time of the switching tube. It has the characteristics of fast response and low power consumption, which can improve the efficiency and stability of switching power supply.

7.Battery charge and discharge management: TL431AIDBZ can be used in battery charge and discharge management circuits to control the charging voltage and discharge cut-off voltage to protect the battery from overcharge or over-discharge.

•Charging voltage control: During the battery charging process, in order to ensure that the battery is charged safely and effectively, the charging voltage needs to be accurately controlled. TL431AIDBZ can set an accurate reference voltage. When the charging voltage reaches this reference voltage, the charging process can be cut off or switched to trickle charging mode to prevent battery overcharging.

•Discharge cut-off voltage protection: When the battery is discharged to a certain low voltage, if the discharge continues, the battery may be damaged. TL431AIDBZ can set a discharge cut-off voltage. When the battery voltage drops to this value, the discharge circuit can be cut off, thereby protecting the battery from excessive discharge damage.

8.Reference voltage in analog circuits: In analog circuits, TL431AIDBZ can be used as a reference voltage source to provide a stable reference voltage for calibrating and adjusting the operating point and gain of the analog circuit.

9.Voltage comparison: Because TL431AIDBZ has high accuracy and stability, it is often used in voltage comparators to detect the magnitude relationship between two voltage signals and control the operations of other circuits based on the comparison results.

10.Adjustable voltage power supply: Because TL431AIDBZ is programmable and can change the target value of the output voltage by adjusting the input voltage, it is often used in adjustable voltage power supplies. It enables precise regulation of output voltage to meet various application requirements.

•Output voltage programming: TL431AIDBZ is programmable, allowing the user to adjust the target value of the output voltage through external resistors or digital control. This flexibility allows adjustable voltage power supplies to be adapted to a variety of different application needs, such as providing the required voltage for different devices or circuits.

11.Stabilized power supply circuit: TL431AIDBZ, as an adjustable precision parallel voltage regulator, is often used in stabilized power supply circuits. It can accurately control the output voltage and achieve stable power output by adjusting the difference between the input voltage and the reference voltage. This makes it widely used in various electronic equipment, such as communication equipment, computers, measuring instruments, etc.


Ⅴ.Absolute Maximum Ratings of TL431AIDBZ
over operating free-air temperature range(unless otherwise noted)

Ⅵ.Electrical Characteristics of TL431AIDBZ
over recommended operating conditions,TA = 25°C(unless otherwise noted)


Ⅶ.Correct installation and use of TL431AIDBZ

1.Choose a suitable circuit location: First, you need to find a suitable location for the TL431AIDBZ in the power circuit. Usually, it will be placed in the part that requires stable output voltage, such as the back end of the power supply output.

2.Connect circuit components:

•Connect the cathode of TL431AIDBZ to the negative pole of the power output.

•Connect the reference terminal (Reference) of TL431AIDBZ to a voltage adjustment point, usually the midpoint of the voltage divider resistor. By adjusting the voltage at this point, you can set the value of the output voltage.

•Connect the anode of TL431AIDBZ to the positive pole of the power output through a suitable resistor. This resistor is called the "voltage divider resistor" and is used to adjust the reference voltage of the TL431AIDBZ.

3.Adjust the output voltage:

•Rotate or adjust this component until the output voltage reaches your desired value. Note, be careful when adjusting to avoid overvoltage or overcurrent.

•Use an adjustable resistor or multi-turn potentiometer to adjust the output voltage. Connect one end of this adjustment component to the midpoint of the voltage divider resistor and the other end to the negative terminal of the power supply output.

4.Add a protection circuit: In order to protect the TL431AIDBZ and power circuit, you can add an overcurrent protection circuit and an overheating protection circuit. These circuits cut off power when the current is too high or the temperature is too high to protect circuit components from damage.

5.Testing and debugging:

•After completing the circuit installation, use a test tool such as a multimeter to measure the output voltage to ensure it meets the requirements.

•If the output voltage is unstable or deviated, the value of the voltage dividing resistor or adjustment component can be adjusted to optimize the stability of the output voltage.


•Please ensure that the temperature of the TL431AIDBZ and its surrounding circuits is within the allowable range to avoid performance degradation or damage caused by overheating.

•During installation and use, be sure to follow relevant safety regulations to avoid potential risks such as short circuit, overvoltage and overcurrent.

Ⅷ.Alternate model of TL431AIDBZ






Frequently Asked Questions

1.Can TL431AIDBZ be used in automotive applications?
Yes, TL431AIDBZ can be used in automotive applications, but it may require additional precautions and ruggedization to withstand automotive operating conditions.

2.How does TL431AIDBZ maintain stability in voltage regulation?
TL431AIDBZ maintains stability by comparing an external voltage reference with its internal 2.5V reference and adjusting its output accordingly.

3.What precautions should be taken when using TL431AIDBZ?
Precautions when using TL431AIDBZ include ensuring proper pin connections, providing proper filtering and decoupling capacitors, and protecting against overvoltage and overcurrent conditions.