The AD5629R/AD5669R devices are low power， octal， 12-/16- bit， buffered voltage-output DACs. All devices are guaranteed monotonic by design. The AD5629R/AD5669R have an on-chip reference with an internal gain of 2. The AD5629R-1/AD5669R-1 have a 1.25 V， 5 ppm/°C reference， giving a full-scale output range of 2.5 V. The AD5629R-2/AD5629R-3 and the AD5669R-2/AD5669R-3 have a 2.5 V 5 ppm/°C reference， giving a full-scale output range of 5 V depending on the option selected. Devices with 1.25 V reference selected operate from a single 2.7 V to 5.5 V supply. Devices with 2.5 V reference selected operate from 4.5 V to 5.5 V. The on-chip reference is off at power-up， allowing the use of an external reference. The internal reference is enabled via a software write. The parts incorporate a power-on reset circuit to ensure that the DAC output powers up to 0 V （AD5629R-1/AD5629R-2， AD5669R-1/AD5669R-2） or midscale （AD5629R-3/AD5669R-3） and remains powered up at this level until a valid write takes place. The part contains a power-down feature that reduces the current consumption of the device to 400 nA at 5 V and provides softwareselectable output loads while in power-down mode for any or all DAC channels.