The TL431 is an adjustable shunt regulator designed to act as an open-loop error amplifier with a 2.5V temperature compensated reference. Its highly accurate 1% bandgap reference is perfect for applications requiring stability and accuracy over temperature and life. Sharp turn-on characteristics and a low temperature coefficient make the TL431 an excellent replacement for many zener diode applications, programmable to any value greater than 2.5V and up to 36V by using two external resistors. As a combination error amplifier and reference, it can be used to manage control loops such as switching power supplies.