The NCP100 is a precision low voltage shunt regulator that is programmable over a voltage range of 0.9 V to 6.0 V. This device features a guaranteed reference accuracy of 1.7% at 25C and 2.6% over the entire temperature range of -40C to 85C. The NCP100 exhibits 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. These characteristics make this device an ideal replacement for zener diodes in numerous application circuits that require a precise low voltage reference. When combined with an optocoupler, the NCP100 can be used as an error amplifier for controlling the feedback loop in isolated low output voltage (2.3 V) switching power supplies. This device is available in TO-92 and in an economical space saving TSOP-5 package.