A Charge-Redistribution Multi-Bit Stochastic-Resonance ADC Enhancing SNDR for Weak Input Signal

Stochastic resonance is known as a phenomenon where the signal-to-noise ratio (SNR) of a nonlinear system improves by adding a proper level of noise. To facilitate this phenomenon, this paper proposes a stochastic-resonance analog-to-digital converter (SR ADC) based on a charge-redistribution capacitor digital-to-analog converter (CDAC). The proposed SR ADC utilizes the same architecture as a charge-redistribution successive approximation register (SAR) ADC. In this paper, the performance of the SR ADC is analyzed in detail to demonstrate its feasibility and advantage over the typical Nyquist ADC. The comparison with the SAR ADC in terms of the signal to noise and distortion ratio (SNDR) reveals that the SR ADC is useful to convert the weak input signal whose amplitude is comparable to the input-referred noise of the comparator.