An Area-Efficient Dual-Mode SAR ADC With 3-Level Analog Prediction to Compensate for Input Range Loss of Mismatch Error Shaping

This paper proposes a sophisticated 3-level analog prediction scheme designed to compensate for the input range loss associated with mismatch error shaping (MES). This innovative approach effectively nullifies prediction errors, enabling the application of MES to both noise-shaping (NS) and Nyquist ADCs, thereby facilitating a versatile dual-mode SAR ADC. Our prototype delivers an impressive SNDR/SFDR of $78.5 / 91.5 \mathrm{~dB}$ within a 31.25 kHz bandwidth, achieving a Schreier FoM of 175.8 dB in NS mode. Notably, in Nyquist mode, the SFDR escalates from 69.7 dB to 83.7 dB at Nyquist input. The proposed ADC, realized in a 65 nm process, features a compact area of only $0.01 \mathrm{~mm}^{2}$, making it the most compact yet efficient design to achieve an SNDR of 78 dB in processes larger than 28 nm.