The TL431 is a three-terminal programmable shunt regulator diode. This monolithic IC voltage reference operates as a low temperature coefficient zener which is programmable from Vref to 36 V with two external resistors. They exhibit a wide operating current range of 1.0 mA to 100 mA with a typical dynamic impedance of 0.22 Ohms. The characteristics of these references make them excellent replacements for zener diodes in many applications such as digital voltmeters, power supplies, and op-amp circuitry. The 2.5 V reference makes it convenient to obtain a stable reference from 5.0 V logic supplies, and since the TL431 operates as a shunt regulator, it can be used as either a positive or negative voltage reference. Features: Programmable Output Voltage to 36 V Voltage Reference Tolerance: ±0.4%, Typ @ 25°C (TL431B) Low Dynamic Output Impedance, 0.22 Ohms Typical Sink Current Capability of 1.0 mA to 100 mA Equivalent Full-Range Temperature Coefficient of 50 ppm/°C Typical Temperature Compensated for Operation over Full Rated Operating Temperature Range Low Output Noise Voltage Pb and Halide-Free Datasheet: http://dlnmh9ip6v2uc.cloudfront.net/datasheets/Components/General%20IC/TL431-D.pdf