TL431 Adjustable Precision Shunt Regulator

The TL431 is a three-terminal adjustable regulator series with guaranteed thermal stability over the temperature ranges applicable. With the help of two external resistors, the output voltage can be adjusted to any value between VREF (approximately 2.5 volts) and 36 volts. The typical dynamic output impedance of these devices is 0.2. Because active output circuitry has a very sharp turn-on characteristic, these devices are an excellent replacement for Zener diodes in many applications.