View tl431a utc datasheet:

UTC TL431A LINEAR INTEGRATED CIRCUIT PROGRAMMABLE PRECISION REFERENCE SOP-8 DESCRIPTION The UTC TL431A is a three-terminal adjustable regulator with a guaranteed thermal stability over applicable temperature ranges. The output voltage may be set to any 1 value between Vref(approximately 2.5V) and 36V with two TO-92 external resistors. It provides very wide applications, including shunt regulator, series regulator, switching regulator, voltage reference and others. 1 FEATURES SOT-89 *Programmable output Voltage to 36V. *Low dynamic output impedance 0.2? SOP-8 1: Cathode 2,3,6,7: Anode 8:Ref. *Sink current capability of 1.0 to 100mA. 4,5: N.C. *Equivalent full-range temperature coefficient of 50ppm/ °C TO-92 1: Ref; 2:Anode; 3:Cathode typical for operation over f