The AD5625R/AD5645R/AD5665R and AD5625/AD5665 members of the nanoDAC? family are low power， quad， 12-/ 14-/16-bit， buffered voltage-out DACs with/without an on-chip reference. All devices operate from a single 2.7 V to 5.5 V supply， are guaranteed monotonic by design， and have an I2 C-compatible serial interface. The AD5625R/AD5645R/AD5665R have an on-chip reference. The LFCSP versions of the AD5625R/AD5645R/AD5665R have a 1.25 V or 2.5 V， 10 ppm/°C reference， giving a full-scale output range of 2.5 V or 5 V; the TSSOP versions of the AD5625R/ AD5645R/AD5665R have a 2.5 V， 5 ppm/°C reference， giving a full-scale output range of 5 V. The WLCSP has a 1.25 V reference. 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 AD5625/AD5665 require an external reference voltage to set the output range of the DAC. The device incorporates a power-on reset circuit that ensures that the DAC output powers up to 0 V （POR = GND） or midscale （POR = VDD） and remains there until a valid write occurs. The on-chip precision output amplifier enables rail-to-rail output swing