A digital-to-analog data converter for converting a digital input signal to an analog output signal is provided. The digital-to-analog data converter includes a register, a decoder, a converting unit and an output unit. During a first period, the decoder decodes least significant bits, and takes the decoded least significant bits as a first control signal for controlling the converting unit to output a first converting current according to the first control signal. During a second period, the decoder decodes most significant bits, and takes the decoded most significant bits as a second control signal for controlling the converting unit to output a second converting current according to the second control signal. The output unit registers the first converting current during the first period, amplifying the second converting current, and combining the amplified second converting current with the registered first converting current as the analog output signal during the second period.