Modeling of CMOS Digital-to-Analog Converters for Telecommunication

This paper gives an overview of some of the effects caused by circuit mismatch and parasitics in binary weighted digital-to-analog (DAC) converters, and, as a special case, a current-steering CMOS converter. Matlab is used as a behavior-level simulator. In telecommunications applications, the frequency-domain parameters are of the greatest importance. Therefore, the characterization of the device and its performance is determined by frequency parameters such as the signalto-noise ratio, spurious-free dynamic range, multitone power ratio, etc. In this paper, we show how these frequency-domain parameters are affected when mismatch errors and finite output impedance are applied to a current-steering CMOS DAC. We discuss how static performance is affected when changing the size of the errors and fundamental circuit parameters. The impact of dynamic errors such as glitches, slewing, and bit skew is discussed. Measurement results from 14-bit DAC’s are also shown to illustrate the correlation with the modeling.