A Low-Offset Low-Noise Sigma-Delta Modulator With Pseudorandom Chopper-Stabilization Technique

Abstract

This paper presents a low-offset low-noise sigma-delta modulator with pseudorandom chopper-stabilization technique. The comparison of the noise-cancellation ability with the correlated double sampling and chopper-stabilization techniques is demonstrated; also, the noise performance of these cancellation techniques is observed and discussed. Using the proposed technique, the modulator achieves 92 dB of dynamic range and -135 dB of noise floor while consuming 950 ¿W from a 3-V supply. Based on the experimental results, the pseudorandom chopper-stabilization technique has a DC offset voltage that is 6 dB lower than that of the chopper-stabilization technique, and retains a thermal noise floor that is 1.6 dB lower than that of the correlated double sampling technique.