Patent attributes
A digital-to-analog converter has a plurality of current cells. Each of the current cells has a level shifter and a current source. The level shifter connects to a first power terminal and a second power terminal to convert a first input signal and a second input signal into a first output signal and a second output signal. The current source has two cascaded MOS transistors connected to the first power terminal in series, a first MOS switch having a gate for receiving the first output signal, and a second MOS switch having a gate for receiving the second output signal. A voltage level of the first power terminal is greater than a voltage level of the second power terminal. When one of the current cells operates, one of the first MOS switch and the second MOS switch of the current source is turned on and operates in a saturation region.