TL431 Dip Shunt Regulator To-92

 
TL431 is a 3-terminal adjustable precision shunt regulator. It works like a programmable zener, or a programmable voltage reference. This listing is the TO-92 through-hole version, with 3 pins.

Its reference voltage is 2.495V typical. With two external resistors, you can set its output from Vref to 36V. It stays stable when the temperature changes, and it turns on sharply, which is why it is a good replacement for a fixed zener diode in many circuits. It can give a steady reference from a 5V supply, and it can work as a positive or a negative voltage reference.

A very common job is in switch-mode power supplies, where it works with an optocoupler to keep the output voltage steady. It is also used for on-board regulation, adjustable power supplies, and voltage monitoring.

Note: it needs a small minimum current to start regulating. Check the maker’s datasheet for your exact part before you use it.

Key Features

• Adjustable precision shunt regulator with 3 pins.
• Works as a programmable voltage reference.
• Can replace a fixed zener in many circuits, with an adjustable output.
• Low dynamic output impedance, so the output stays stable.
• Can sink current from 1 to 100 mA.
• Used in power supplies, inverters, and voltage monitoring circuits.

Technical Specifications

These values are from the TI TL431 datasheet.

Who It Fits

This part fits a through-hole TO-92 board. It is for repair and building work where a small adjustable reference is needed.

Check Before Ordering

• Check the pin order for TO-92: Reference, Anode, Cathode.
• Check that your circuit voltage is within 36V.
• Check that your current is within the 1 to 100 mA range.

Other Names Shoppers Use

This part is also searched as “TL431 adjustable shunt regulator” and “programmable precision reference”.

If this part is not available, use one of these instead

Substitutes you can buy at SunTech Mall

The same TL431 chip is also sold in surface-mount packages. These are the TL431 versions in stock at SunTech Mall at the time of this edit:

• TL431 Smd Shunt Regulator Sop-8
• TL431 Smd Shunt Regulator Sot-89
• TL431 Smd Shunt Regulator Sot-23

Warning: same chip, same job. Only the package is different. The pins and footprint are different. For a through-hole board, check the pinout first. You will need SMD soldering or an adapter.

Other names for the same part (good to know)

KA431, LM431, μA431, YL431, and S431 are parts from the same TL431 family, per published cross-reference guides. They are not listed on SunTech Mall at this time. Note: copies from other makers can differ a little in tolerance and minimum current. For precise work, check the maker’s datasheet first.

Frequently Asked Questions

What does TL431 do?

It gives a stable, adjustable voltage reference. It can also work as an error amplifier in a power supply.

What voltage can it set?

With two external resistors, it can set an output from Vref to 36V. Its reference voltage is 2.495V typical.

Can I use the SOP-8, SOT-89, or SOT-23 version instead of TO-92?

Yes, for the same TL431 job, but only with care. The package, pins, and footprint are different. Check the pinout first. You will need SMD soldering or an adapter on a through-hole board. See: TL431 Smd Shunt Regulator Sop-8, TL431 Smd Shunt Regulator Sot-89, and TL431 Smd Shunt Regulator Sot-23.

Is KA431 the same as TL431?

KA431 is a part from the same TL431 family, but it is not listed on SunTech Mall at this time. For precise work, check the maker’s datasheet before you use it.

How do I check before replacing?

Check the pin order, the package footprint, the circuit voltage within 36V, and the current within 1 to 100 mA. Then check the maker’s datasheet for your exact part.

What is the price?

Please check the live price on this page. It is shown with the product details above.

Related Guide

For a simple guide to how the TL431 works, read: TL431 Shunt Regulator guide.