Dynamic Element Matching for Low-power ΣΔ Modulator with R-C based internal DAC

The use of internal resistive-capacitive MDAC in ΣΔ modulators requires a special dynamic element matching (DEM) approach. This paper proposes two modified versions of the DWA method capable to obtain very high linearity with a large number of quantization levels (16 or 32). The benefit of a 4-5 bit DAC enables very low OSR and the use of a second order modulator for the conversion of 8 MHz bandwidth with 10-12 bit of accuracy and very low power consumption. Extensive behavioral simulations verify the effectiveness of the proposed methods with element mismatches as large as 1%.