By default, the DACx300x operate from an external reference input. The external reference option can also be selected by configuring the VOUT-GAIN-X field in the DAC-X-VOUT-CMP-CONFIG register appropriately. Write 1 to the DIS-MODE-IN bit in the DEVICE-MODE-CONFIG register to minimize IDD. The external reference can be between 1.7 V and VDD. Equation 3 shows DAC transfer function when the external reference is used. The gain at the output stage of the DAC is always 1x in the external reference mode.