A data driver includes a data signal converter to convert image data to a data signal, an output buffer to output the data signal to a data line, a first cascode circuit connected to the output buffer and including a plurality of transistors, a first noise attenuator connected to a first node between the output buffer and the first cascode circuit, and to attenuate a first current noise, a second cascode circuit connected to the output buffer and including a plurality of transistors, a second noise attenuator connected a second node between the output buffer and the second cascode circuit, and to attenuate a second current noise, a current integrator to generate an integrated voltage by integrating a first current flowing through the first cascode circuit and a second current flowing through the second cascade circuit, and an analog-digital converter (ADC) to convert the integrated voltage to a digital signal.