A Wideband 6th Order Programmable Bandpass DEM Implementation for a Nyquist DAC

Abstract

This paper presents a 6th order programmable bandpass dynamic-element-matching (DEM) that shapes the static mismatch error of a Nyquist DAC for any choice of center-frequency. The mismatch error can be shaped over a narrow or wide band, and up to 20% of Fs depending on the target application. This work demonstrates that for a 12-bit Nyquist DAC (5T-7B), the lowest in-band SFDR and IMD3 is 88dB and 80dB respectively, for various configurations of the DEM. The DEM hardware is implemented onto a XILINX FPGA using the System-Generator for DSP™ tool with results obtained for 155MHz Fs.