A current source DAC has calibration of the current sources used for providing the analog output. There are two outputs, one of which provides the output current or else a differential output is provided. The calibration is cyclic and the current source outputs switched to the output terminals are selected as a function of the point within the calibration cycle. The current stage of the cyclic calibration process is thus taken into account in the D/A conversion. For example, the average time since calibration for all current sources having outputs switched to the first output may be approximately equal to the average time since calibration for all current sources having outputs switched to the second output. In this way, the average current of the cells switched to one terminal is identical to the average current of the cells switched to the other terminal, and the average current of the cells switched to each terminal remains constant in time irrespective of the digital signal value being converted. This ensures DAC linearity.
CROSS REFERENCE TO RELATED APPLICATION
This patent application is a continuation of U.S. patent Ser. No. 10/326,168 (now U.S. Pat. No. 6,738,000), filed Dec. 23, 2002, which is a continuation of Ser. No. 09/908,569, filed Jul. 20, 2001 (now U.S. Pat. No. 6,501,402), which are both incorporated herein by reference in their entireties.
