Errors of Multiplying D/A Converters Used for Precise AC Voltage Division

High-resolution multiplying digital-to-analog converters (MDACs) are often used as digitally controlled ac voltage dividers in precise instruments and measurement systems. Proper application of these converters requires knowledge of their parameters, especially amplitude and phase errors, which are usually not specified by MDAC manufacturers. This paper presents the results of investigations of voltage amplitude ratio errors and phase errors, as well as the time stability of voltage ratio and phase shift of selected commercial 16- and 18-bit MDACs. These parameters were measured with a dedicated high-resolution sampling system. The amplitude ratio and phase errors were determined as a function of the MDAC digital input word. Phase errors were also determined as a function of frequency.