The TS431I/431AI/431BI integrated circuits are three- terminal programmable shunt regulator diodes. These monolithic IC voltage r eferences operate as a low temperatur e coefficient zener which is programmable from Vr ef to 36 volts w ith two external resistors. These devices exhibit a w ide operating current range of 1.0 to 100mA with a typical dynamic impedance of 0.22. The characteristics of these references make them excellent replacements for zener diodes in many applications such as digital voltmeters, power supplies, and op amp c ircuitry . The 2.5volt reference makes it convenient to obtain a stable reference from 5.0v olt logic supplies, and since The TS431I/431AI/431BI oper ates as a shunt r egulator, it can be used as either a pos itive or negative stage reference.