Improved design methodology for high-speed high-accuracy current steering D/A converters

This paper describes a sizing and design methodology for high-speed high-accuracy current steering D/A converters taking into account mismatching in all the transistors of the current source cell. The presented method allows a more accurate selection of the optimal design point without introducing arbitrary safety margins, as was done in the previous literature. This methodology has been applied to the design of a CMOS 12-bit 400 MHz current-steering segmented D/A converter. Commercial CAD tools are used to automatically lay out regular structures of the DAC, specially the current source array, following an optimal two-dimensional switching scheme to compensate for systematic mismatch errors.