The AS431 is a three-port adjustable shunt regulator with guaranteed thermal stability over the entire operating range. It is characterised by sharp switch-on characteristics, low temperature coefficient and low output impedance to make it the ideal replacement for zener diodes in applications such as switching power supplies, chargers and other adjustable regulators. The output voltage of the AS431 can be set to any value between VREF (2.5 V) and the corresponding maximum cathode voltage (36 V). The AS431 precision reference is available in two voltage tolerances: 0.5% and 1.0%.