This part is a kind of semiconductor called AZ431-A.

Function of this product has ADJUSTABLE PRECISION SHUNT REGULATORS.

Manufacturers : Diodes

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AZ431-A ADJUSTABLE PRECISION SHUNT REGULATORS Description Features The AZ431-A is a three-terminal adjustable shunt regulator with guaranteed thermal stability over a full operation range. It features sharp turn-on characteristics, low temperature coefficient and low output impedance, which make it ideal substitute for Zener diode in applications such as switching power supply, charger and other adjustable regulators. The output voltage of AZ431-A can be set to any value between VREF (2.5V) and the corresponding maximum cathode voltage (36V). The AZ431-A precision reference is offered in two voltage tolerance: 0.4% and 0.8%. This IC is available in 4 packages: TO92 (bulk or ammo packing), SOT23, SOT25 and SOT89.  Programmable Precise Output Voltage from 2.5V to 36V  High Stabilit [ ... ]

AZ431-A PDF Datasheet Download