TL431 Precision Programmable Reference

TL431 is a shunt regulator diode IC available in TO-92 and other packages. This is a three terminal IC. The output voltage can be adjusted from 2.5V to 36V with the help of a resistor divider connected with its reference pin or pin1. Moreover this IC can be operated from 1mA to 100mA current range with typical ouput impedance value of 0.22 Ohms. It is also capable to provide stable performance on its wide temperature range. It can be used as a replacement for the zener diode in wide variety of applications because it works just like a zener diode the only difference is that its output is adjustable.

TL431 has many uses in electronics, its most common uses are under voltage and over voltage monitoring, window voltage monitoring etc. and it can also be found in power supplies as a reference voltage source.

By looking at the internal block diagram circuit shown below we can see that the internal circuitry of the chip contains an NPN transistor at the output that is biasing from an opamp which has 2.5V precise voltage.

Applications

Voltage Comparator Circuits

Battery Charger & Monitor Circuits

Solar Applications

Switching Supply Circuits

Replacement and Equivalent / Other Part Numbers

KIA431, TL432, LM336Z5, TA76431S(TE6,F,M)