Sine-Shaping Mixer for Continuous-Time ΣΔ ADCs
Résumé
Sine-shaping of feedback DAC current in continuous-time ΣΔ ADCs is an effective solution to enhance their immunity to clock jitter. In this paper, a simple mixer circuit for producing a sine-shaped output in continuous-time ΣΔ ADCs is introduced. The proposed solution does not need extra clock source or synchronization circuit, as the mixer utilizes the same clock applied to the comparator. It is also shown the that the proposed circuit is immune to temperature and process variations. Simulation results of the proposed circuit implemented in 130 nm CMOS process show good agreement with the expected results.