Especially in case of R2R ladder DACs it is quite easy to change the output voltage of the DAC by changing its reference voltage . The SDA-2, a new generation DAC module was designed to get the best regulation possible. The result of this process is an extremely high linearity, right down to -140 dB, which gives our products a realistic 24 bit dynamic range.
官网说法,看来确实是控制ref电压
那个看了下芯片定义,应该只用了一个音量通道。