The AD5623R/AD5643R/AD5663R， members of the nanoDAC? family， are low power， dual 12-， 14-， and 16-bit buffered voltageout digital-to-analog converters （DAC） that operate from a single 2.7 V to 5.5 V supply and are guaranteed monotonic by design. The AD5623R/AD5643R/AD5663R have an on-chip reference. The AD5623R-3/AD5643R-3/AD5663R-3 have a 1.25 V， 5 ppm/°C reference， giving a full-scale output of 2.5 V; and the AD5623R-5/AD5643R-5/AD5663R-5 have a 2.5 V， 5 ppm/°C reference， giving a full-scale output of 5 V. The on-chip reference is off at power-up， allowing the use of an external reference; and all devices can be operated from a single 2.7 V to 5.5 V supply. The internal reference is turned on by writing to the DAC. The parts incorporate a power-on reset circuit that ensures the DAC output powers up to 0 V and remains there until a valid write takes place. The part contains a power-down feature that reduces the current consumption of the device to 480 nA at 5 V and provides software-selectable output loads while in powerdown mode.