TL431 Shunt Regulator: How to Test and Replace?
Joan
26 April 2022
9965
TL431IZ
STMicroelectronics
IC VREF SHUNT 36V 2.21% TO92-3
Unit Price: $1.015190
Ext Price: $1.02
Purchase Guide
-40°C~105°C TA Adjustable PMIC TL431 1 Channel TO-226-2, TO-92-2 (TO-226AC)
How to check if TL431 is broken? If TL431 is really broken, then how to replace it? These two kinds of problems will be discussed in this article. Furthermore, Huge range of Semiconductors, Capacitors, Resistors and IcS in stock. Welcome RFQ.
How to TEST TL431 Voltage Reference / TL431A TL432 KIA431 Shunt Regulator circuit
Catalog
- What is TL431?
- TL431 Pinout
- TL431 CAD Model
- TL431 Features
- Specifications
- TL431 Functional Block Diagram
- TL431 Equivalent
- How to Measure TL431?
- How to Test TL431?
- TL431 Replaceable Models
- Conclusion
- Parts with Similar Specs
- TL431 Applications
- TL431 Package
- TL431 Manufacturer
- Datasheet PDF
What is TL431?
TL431 is a 2.5～36V Adjustable Shunt Regulator.With its excellent performance and low price, it can be widely used in single-chip precision switching power supplies or precision linear regulated power supplies. In addition, TL431 can also form a voltage comparator, power supply voltage monitor, delay circuit, precision constant current source, etc.
The TL431 isadjustable shuntvoltage reference with guaranteed temperaturestability over the entire operating temperaturerange. The device temperature range is extendedfor the automotive version from -40 °C up to+125 °C. The output voltage can be set to anyvalue between 2.5 and 36 V with two externalresistors. The TL431 operateswith awide current range from 1 to 100 mA with a typicaldynamic impedance of 0.22 Ω.
This article will introduce TL431systematically from its features, pinout to its specifications, applications, also including TL431datasheet and so much more.
TL431 Pinout
The following figure is the diagram of TL431Pinout.
Pinout
TL431 CAD Model
The followings are TL431Symbol, Footprint, and 3D Model.
PCB Symbol
PCB Footprint
3D Model
TL431 Features
●AEC-Q100 qualified
●Adjustable output voltage: 2.5 to 36 V
●Sink current capability: 1 to 100 mA
●Typical output impedance: 0.22 Ω
●1% and 2% voltage precision
●Automotive temp. range -40 °C to +125 °C
Specifications
STMicroelectronics TL431IZ technical specifications, attributes, parameters and parts with similar specifications to STMicroelectronics TL431IZ.
Type
Parameter
Lifecycle Status
ACTIVE (Last Updated: 7 months ago)
Factory Lead Time
8 Weeks
Mount
Through Hole
Mounting Type
Through Hole
Package / Case
TO-226-2, TO-92-2 (TO-226AC)
Number of Pins
3
Operating Temperature
The operating temperature is the range of ambient temperature within which a power supply, or any other electrical equipment, operate in. This ranges from a minimum operating temperature, to a peak or maximum operating temperature, outside which, the power supply may fail.
-40°C~105°C TA
Packaging
Semiconductor package is a carrier / shell used to contain and cover one or more semiconductor components or integrated circuits. The material of the shell can be metal, plastic, glass or ceramic.
Bulk
Tolerance
±2.21%
JESD-609 Code
e3
Part Status
Parts can have many statuses as they progress through the configuration, analysis, review, and approval stages.
Active
Moisture Sensitivity Level (MSL)
1 (Unlimited)
Number of Terminations
3
ECCN Code
EAR99
Temperature Coefficient
The resistance-change factor per degree Celsius of temperature change is called the temperature coefficient of resistance. This factor is represented by the Greek lower-case letter “alpha” (α). A positive coefficient for a material means that its resistance increases with an increase in temperature.
100 ppm/°C
Terminal Finish
Matte Tin (Sn) - annealed
Terminal Position
BOTTOM
Number of Functions
1
Base Part Number
TL431
Pin Count
a count of all of the component leads (or pins)
3
Number of Outputs
1
Output Voltage
36V
Output Type
Adjustable
Max Output Current
The maximum current that can be supplied to the load.
100mA
Number of Channels
1
Trim/Adjustable Output
YES
Analog IC - Other Type
THREE TERMINAL VOLTAGE REFERENCE
Nominal Supply Current
Nominal current is the same as the rated current. It is the current drawn by the motor while delivering rated mechanical output at its shaft.
1mA
Max Output Voltage
The maximum output voltage refers to the dynamic area beyond which the output is saturated in the positive or negative direction, and is limited according to the load resistance value.
36V
Max Input Voltage
37V
Reference Voltage
A voltage reference is an electronic device that ideally produces a fixed (constant) voltage irrespective of the loading on the device, power supply variations, temperature changes, and the passage of time. Voltage references are used in power supplies, analog-to-digital converters, digital-to-analog converters, and other measurement and control systems. Voltage references vary widely in performance; a regulator for a computer power supply may only hold its value to within a few percent of the nominal value, whereas laboratory voltage standards have precisions and stability measured in parts per million.
2.495V
Reference Type
a code object that is not stored directly where it is created, but that acts as a kind of pointer to a value stored elsewhere.
Shunt
Min Output Voltage
2.495V
Temp Coef of Voltage-Max
82.924 ppm/°C
Current - Cathode
1mA
Radiation Hardening
Radiation hardening is the process of making electronic components and circuits resistant to damage or malfunction caused by high levels of ionizing radiation, especially for environments in outer space (especially beyond the low Earth orbit), around nuclear reactors and particle accelerators, or during nuclear accidents or nuclear warfare.
No
RoHS Status
RoHS means “Restriction of Certain Hazardous Substances” in the “Hazardous Substances Directive” in electrical and electronic equipment.
ROHS3 Compliant
Lead Free
Lead Free
0 Similar Products Remaining
TL431 Functional Block Diagram
The following is the Block Diagram of TL431.
Block Diagram
TL431 Equivalent
| Model number | Manufacturer | Description |
| TL431IZT | STMicroelectronics | Adjustable micropower shunt voltage reference |
How to Measure TL431?
(1) Measurement of forward and reverse resistance of zener diode
The multimeter range is set to Rxlk, the black pen is connected to A pole, and the red pen is connected to K pole. At this time, the forward resistance of the Zener diode is measured. To measure the reverse resistance elbow, the range should be set to Rxlk. The data measured with the MF47 meter is: the forward resistance is 6xlkΩ, and the reverse resistance should be infinite.
(2) Measurement of the forward and reverse resistance of Rpole and A and K poles
The multimeter range is set to Rxlk, the black pen is connected to the Rpole, and the red pen is connected to the A pole. The resistance should be 35xlkΩ. The resistance of interchangeable test leads should be 10xlkn. Connect the black pen to the Rpole and the red pen to the K pole. The resistance should be 11×lkΩ. If the test leads are interchanged, the resistance should be infinite.
(3) Measurement of the forward and reverse resistance of K pole and A, Rpole
The multimeter range is set to Rxlk, the black pen is connected to the K pole, and the red pen is connected to the Rpole. At this time, the resistance is infinite. Exchange the test leads, the resistance should be 11×lkΩ. Connect the black pen to the K pole and the red pen to the A pole, and the resistance should be infinite. If the test leads are interchanged, the resistance is 8xlkΩ.
How to Test TL431?
As shown in the figure is circuit tested by TL431. For the power supply, it is a 0~20V maintenance power supply.
We connected an ammeter between the K pole and the power supply. This is done in order to clearly observe the changes in the current of the K pole as the voltage of the G pole changes. We also connect a voltmeter between K and A. In this way, we can clearly observe the changes in the output of the TL431 with the power supply.
Before the test, adjust the potentiometer to near the middle value. Then, use a digital meter to measure the K pole-to-ground voltage and adjust the voltage output of the maintenance power supply. At this time, it can be found that the voltage between the K pole and the ground has only two states: one is about 2V (low level); the other is equal to the power supply voltage (high level).
TL431 Circuit
Then how to judge whether TL431 is normal?
For the on-line TL431 power supply error comparator, the external maintenance power supply can be used to detect. Connect the maintenance power supply to the sampling point of the TL431, and when the voltage is higher than the nominal voltage, the TL431 will be turned on and the K-pole voltage will be low.
That is to say, when the power supply voltage increases, the TL431 is turned on, so that the diode of the photocoupler is turned on, so that the transistor is in a saturated state, and the turn-on time of the primary power switch is finally shortened (reducing the duty cycle). In this way, the output voltage is reduced. If the maintenance voltage is reduced, the TL431 will be cut off, the K pole voltage will be high, and the diode of the photocoupler will be cut off, which will make the Triode in the cut-off state, and finally control the increase of the turn-on time of the primary power switch of the transformer (increase the duty cycle). Increase the output voltage. The closed-loop voltage stabilizing circuit of the switching power supply uses the TL431 on or off two states to adjust the duty cycle of the switch to control the stability of the output voltage.
When measuring the multimeter, if the resistance between the poles of the lC is normal, the TL431 can be judged to be normal. When using the maintenance power supply power-on test, in the case of changing the power supply voltage, if the TL431 pole to the ground has two changes of high and low levels, the TL431 can be judged to be normal.
TL431 Replaceable Models
When TL431 is damaged, if there is no replacement of the same model, it can be directly replaced with KA431, μA431, LM431, YL431, S431, etc.
TL431 suffix letters indicate product level and operating temperature range.
●C is commercial product (-10℃～+70℃);
●I is an industrial product (-40℃～+85℃);
●M is military product (-55℃～+125℃).
Conclusion
In summary, it is the introduction of How to Test TL431 and its Replacement.TL431 has a wide range of applications. It can be used as a precision reference voltage source, and can also be used to replace a regulator tube to form a parallel adjustable regulated power supply. It can also be used as a constant current source and voltage detection circuit. In addition, in the switching power supply, TL431 can also be used as a simple error amplifier.
Parts with Similar Specs
The three parts on the right have similar specifications to STMicroelectronics & TL431IZ.
Image
Part Number
Manufacturer
Package / Case
Number of Pins
Max Output Current
Max Input Voltage
Min Output Voltage
Output Voltage
Max Output Voltage
Tolerance
Temperature Coefficient
View Compare
TL431IZ
STMicroelectronics
TO-226-2, TO-92-2 (TO-226AC)
3
100 mA
37 V
2.495 V
36 V
36 V
±2.21%
100 ppm/°C
TL431CZ
STMicroelectronics
TO-226-3, TO-92-3 (TO-226AA)
3
100 mA
37 V
2.495 V
36 V
36 V
±2.21%
100 ppm/°C
TL431IZVSTL431CZTL431CZT
STMicroelectronics
TO-226-2, TO-92-2 (TO-226AC)
3
100 mA
37 V
2.495 V
36 V
36 V
±2.21%
100 ppm/°C
TL431IZVSTL431CZTTL431CZ-AP
STMicroelectronics
TO-226-2, TO-92-2 (TO-226AC) (Formed Leads)
3
100 mA
37 V
2.495 V
36 V
36 V
±2.21%
100 ppm/°C
TL431IZVSTL431CZ-APTL431ILP
Texas Instruments
TO-226-3, TO-92-3 (TO-226AA)
3
100 mA
37 V
2.495 V
36 V
36 V
±2.2%
34 ppm/°C
TL431IZVSTL431ILP
TL431 Applications
●Power supply
●Industrial
●Automotive
TL431 Package
The following diagrams show the TL431Package.
TO-92 ammopack and tape and reel package outline
TO-92 bulk package outline 1
TO-92 bulk package outline 2
TL431 Manufacturer
STMicroelectronics is a global independent semiconductor company and is a leader in developing and delivering semiconductor solutions across the spectrum of microelectronics applications. An unrivaled combination of silicon and system expertise, manufacturing strength, Intellectual Property (IP) portfolio and strategic partners positions the Company at the forefront of System-on-Chip (SoC) technology and its products play a key role in enabling today's convergence trends.
Datasheet PDF
Download datasheets and manufacturer documentation for STMicroelectronics TL431IZ.
- Datasheets :
TL431 Datasheet
Frequently Asked Questions
How many pins of TL431IZ?
3 Pins.
What’s the operating temperature of TL431IZ?
-40°C~105°C TA.
What is the essential property of the TL431?
The TL431 is adjustable shunt voltage reference with guaranteed temperature stability over the entire operating temperature range.
What is the Use of TL431?
The TL431 is a "Programmable Precision Reference" and is commonly used in switching power supplies, where it provides feedback indicating if the output voltage is too high or too low. By using a special circuit called a bandgap, the TL431 provides a stable voltage reference across a wide temperature range.
What is TL431 Transistor?
The TL431 is a Regulator Diode whose output voltage can be programmed by changing the value of resistors connected to it. It acts almost like a Zener diode except for that the voltage rating of this IC is programmable. It is commonly used to provide negative or positive voltage references.
How does a Shunt Regulator Work?
The Shunt Regulator or Shunt Voltage Regulator is a form of voltage regulator where the regulating element shunts the current to ground. The shunt regulator operates by maintaining a constant voltage across its terminals and it takes up the surplus current to maintain the voltage across the load.
