The ADR291 and ADR292 are low noise, micro-power precision voltage references that use an XFET reference circuit. The new XFET architecture offers significant performance improvements over traditional band gap and buried Zener based references. Improvements include one quarter the voltage noise output of band gap references operating at the same current, very low and ultralinear temperature drift, low thermal hysteresis, and excellent long-term stability. The ADR29x family is a series of voltage references providing stable and accurate output voltages from supplies as low as 2.8 V for the ADR291. Output voltage options are 2.5 V and 4.096 V for the ADR291 and ADR292, respectively.