Data driver and organic light emitting diode display device using the same

A data driver and an organic light emitting diode display device using the same are disclosed. The data driver includes a digital to analog conversion unit for converting a digital signal into either a positive polarity analog signal or a negative polarity analog signal, and an output circuit unit for outputting either the positive polarity analog signal or the negative polarity analog signal, as an output signal, to a transistor that supplies a current to an organic light emitting diode (OLED).