A number of unit cells of a digital-to-analog converter (DAC) may be simultaneously activated to generate an analog signal. However, while each unit cell may be generally the same, there may be variations such as non-linearity or noise in the analog output depending on which unit cells are activated for a given digital signal value. For example, as additional unit cells are activated for increased values of the analog signal, the fill order in which the unit cells are activated may affect the linearity/noise of the DAC. The decision units may be programmable to select which branches of the fractal DAC to activate, changing the fill order based on a fill-selection signal. The fill order may be set by a fill controller via the fill-selection signal to account for manufacturing variations, gradients in the supply voltage, output line routing, and/or environmental factors such as temperature.