The SFDR property is one of the most important dynamic properties of a DAC. It is limited by the dynamic nonlinearity errors. For a current-steering DAC, one of the most important nonlinearity errors is the delay differences among the current sources. In this paper, a mathematical model is proposed that explains the impact of delay differences on the SFDR of a thermometic DAC. A formula with clear physical meaning is derived. Simulations show that the formula and behavior level simulations fit very well. These results are also consistent with measurement results from a real chip.
Published in:
Circuits and Systems, 2003. ISCAS '03. Proceedings of the 2003 International Symposium on
(Volume:1
)
Date of Conference: 25-28 May 2003