A 12-bit 100-MS/s Pipeline SAR ADC for Professional Medical Field

This paper presents a high-precision, low-power pipeline-SAR ADC designed for wearable device for professional medical use. The proposed ADC consists of residue amplifier, digital control circuit and two SAR ADCs. In both the first and second stage of the proposed ADC, the time sequence of monotonic capacitor switching is adopted, which reduces the power consumption of capacitor array and total capacitance. In addition, an interstage gain error shaping technique is introduced into the capacitor array of two SAR ADCs, which reduces the influence of gain error introduced by residue amplifier. Redundant bit calculation is also used, which tolerates some nonlinearity of the circuit. The ADC is simulated based on 65nm technology, achieves 61 dB SNDR under the input signal of 10MHz.