Analysis of the effect of mismatch on nonlinearity in hybrid RC-DAC

This paper is dedicated to the analysis of the effect of elements mismatch on the nonlinearity of N-bit hybrid segmented RC-digital-to-analog converter. In the structure of the hybrid digital-to-analog converter under consideration, a binary capacitive segment processes the most significant bits, whereas a unary resistive segment processes the least significant bits. Since the consi¬dered digital-to-analog converter is heterogenous, the elements of both segments differ by the type (resistors or capacitors) and area. This causes an optimal ratio of segments resolutions to shift in respect to the total DAC area minimization. Therefore, the goal of the current research is to obtain an expression for optimal segments resolutions in dependance on the ratio of unit capacitor and resistor areas. For this purpose, a parametric mathematical model of the considered converter has been developed in MATLAB. The elements arrays of both segments are influenced by random errors. The simulation of differential and integral nonlinearities has been carried out, which demonstrated a lower contribution of the resistive segment on nonlinearity, in contrast to the capacitive one. Besides, the increment of a capacitive segment resolution improves the yield of both nonlinearities.