A digital-to-analog converter using capacitors and an operational amplifier, which can be highly integrated due to its small area and which can rapidly perform a stable converting operation. The digital-to-analog converter includes a data input unit, a first conversion unit, a second conversion unit, and a signal output unit. When digital data is input to the data input unit, the data input unit is connected to the first conversion unit or the second conversion unit. The first conversion unit charges a first charging capacitor with a voltage corresponding to the input digital data and distributes the charged charges to a first distribution capacitor. The second conversion unit charges a second charging capacitor with the voltage corresponding to the input digital data and distributes the charged charges to a second distribution capacitor. The signal output unit outputs an analog data signal corresponding to the voltage across the first distribution capacitor or the voltage across the second distribution capacitor in response to a select control signal.
A digital-to-analog converter (DAC) can minimize the increase of an area caused by increase of number of bits. The DAC includes a coarse resistor-string digital-to-analog conversion unit for selectively outputting 2.sup.N-level analog voltages in response to upper N-bit digital data, wherein N is a natural number greater than or equal to 2, a fine resistor-string digital-to-analog conversion unit for selectively outputting 2.sup.N-level analog voltages in response to lower N-bit digital data, wherein the 2.sup.N-level analog voltages is obtained by dividing a level of unit voltage of the coarse resistor-string digital-to-analog conversion unit into 2.sup.N-levels, and a voltage combining unit for outputting 2.sup.2N-level analog output signals by combining the output of the coarse resistor-string digital-to-analog conversion unit and the output of the fine resistor-string digital-to-analog conversion unit.
