The TLV431A and B series are precision low voltage shunt regulators that are programmable over a wide voltage range of 1.24 V to 16 V. The TLV431A series features a guaranteed reference accuracy of 1.0% at 25C and 2.0% over the entire industrial temperature range of -40C to 85C. For TLV431B series, the accuracy is even higher, it's 0.5% and 1.0% respectively. These devices exhibit a sharp low current turn-on characteristic with a low dynamic impedance of 0.20 W over an operating current range of 100 mA to 20 mA. This combination of features makes this series an excellent replacement for zener diodes in numerous applications circuits that require a precise reference voltage. When combined with an optocoupler, the TLV431A/B can be used as an error amplifier for controlling the feedback loop in isolated low output voltage (3.0 V to 3.3 V) switching power supplies. These devices are available in e c o n o m i c a l T O -9 2 -3 a n d m i c r o s i z e T S O P -5 a n d SOT-23-3 packages.