Thursday, December 2, 2021

High Precision 5 Volts 3 Amp Voltage Regulator Circuit using TL431 + PCB

Circuits with a high level of sensitivity require a stable supply, they are generally difficult to be powered by power supplies, due to the high level of sensitivity needed to provide stable voltage in the circuit.

However, we are introducing a stabilized power supply with an accurate output to power any sensitive circuit, such as microcontroller circuits, microprocessor circuits, RF transmission, PICs, and so on.

Today we are going to build a very precise circuit, which uses a very well-known component that is widely used in SMPS power supplies, especially ATX PC power supplies, “which looks more like a transistor”.

The 3-Pin TL431 Integrated Circuit, It offers better stability, less temperature deviation (VI (dev)) and less reference current (Iref) for greater system accuracy.

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The TL431 device is an adjustable tap regulator with thermal stability specified in the applicable automotive, commercial, and military temperature ranges.

The output voltage can be set to any value between Vref (approximately 2.5V) to 36V, with two external resistors. These devices have a typical output impedance of 0.2 Ω.

The active output circuitry provides a very crisp activation characteristic, making these devices excellent replacements for Zener diodes in many applications such as integrated regulation, tunable power supplies and switched power supplies.


  • Reference voltage tolerance at 25°C
  • 0.5% (class B)
  • 1% (class A)
  • 2% (standard class)
  • Adjustable output voltage: Vref to 36V
  • Operation from -40 °C to 125 °C
  • Typical temperature deviation (TL43xB)
  • 6 mV (temperature C)
  • 14 mV (I Temp, Q Temp)
  • Low output noise
  • 0.2 Ω typical output impedance
  • Sink current capacity: 1 mA to 100 mA
  • Application
  • Adjustable voltage and current reference
  • Secondary lateral adjustment in Flyback SMPSs
  • Zener Replacement
  • voltage monitoring
  • Comparator with integrated reference

In Figure 2 below, we have the schematic diagram of the High Precision Voltage Regulator Circuit with TL431 IC, the LM350 IC, provides a current of up to 3 Amps.

Fig. 1 - High Precision 5 Volts 3 Amp Voltage Regulator Circuit - TL431

With the TL431 IC, they provide a precise 5V output, which is often necessary for precision microcontrollers, sensitive equipment, that require a stabilized voltage, this circuit is ideal for that.

The power supply must provide a current of at least 3 Amps. Its input voltage must be greater than 7 Volts, to avoid overheating the LM350 IC, voltages no greater than 15V must be used.

Components List

  • CI 1 ......... Voltage Regulator Circuit LM350
  • CI 2 ......... Adjustable Regulator Circuit TL431
  • R1 ........... 8K2Ω Resistor (grey, red, red)
  • R2, R3 ..... Precision resistor 243Ω 1% (red, yellow, orange, black, brown)
  • P1, P2 ..... Soldering terminals on 2-pin PCI
  • Others ..... Printed Circuit Board, tin, wires, etc.


We provide the files with the PCB, the schematic, the PDF, GERBER and JPG, PNG and provide a direct link for free download and a direct link, "MEGA".

Fig. 2 - High Precision 5 Volts 3 Amp Voltage Regulator Circuit - TL431

Click on the direct link to download the files: Layout PCB, PDF, GERBER, JPG

If you have any questions, suggestions or corrections, please leave them in the comments and we will answer them soon.

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My Best Regards!!!

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