A Simplified First Order Mismatch Shaping DAC for Sigma-Delta ADCs

A dynamic element matching (DEM) algorithm is introduced for use in multibit, low oversampling ratio (OSR) sigma-delta data converters. This algorithm employs the tree-structured digital encoder DAC with a simplified class of switching technique. Making use of this simple and intuitive switching strategy a first order noise shaping with the low hardware complexity is achieved. The occurrence of the in-band signal dependent tone, when using this technique is reduced in comparison with other DEM techniques at the expense of some degradation in signal to noise ratio (SNR) especially at low OSR applications.

Keywords:

Sigma-delta ADC , mismatch shaping