AN OVERSAMPLED SIGMA-DELTA A D CONVERTER USING UGB INTEGRATOR WITH GAIN-ERROR COMPENSATOR/

An integrator using UGB (unity-gain buffer) is proposed. The UGB has g ain error. To improve the gain error of UGB in the integrator, a compe nsation technique of the gain error of UGB is proposed. Next, second-o rder SIGMADELTA A/D converter using UGB integrator with gain-error com pensator is proposed. In the proposed circuit, the influence of input- output characteristic is simulated. In the simulation results, the imp rovement is confirmed. In addition, performance limiting factors due t o non ideal effects, e.g., parasitic capacitance and offset voltage, a re considered. Validity of the proposed compensation technique for eac h factor is confirmed in the simulation results.