The TL431ACDT is a programmable three-terminal adjustable shunt regulator from STMicroelectronics. This device consists of an adjustable precision 2.5V reference and an error amplifier in a three-pin SOT-23 surface-mount package. It provides user-defined voltage regulation over a wide range of operating conditions and power dissipation. The output voltage can be set at any voltage from 1.24V to 36V with a simple external resistor network. The TL431ACDT also features a wide operating input voltage range, low quiescent current, fast line transient response, and tight load regulation. The device also offers excellent reverse input protection and high output impedance.