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Summary: This paper presents an energy‐efficient fully differential switching scheme for successive approximation register (SAR) analog‐to‐digital converters (ADCs). During the sampling phase, the top and bottom plates of all capacitors except most significant bit (MSB) capacitors are grounded in digital‐to‐analog converter (DAC) arrays. The input signals are bottom plate sampled on MSB capacitors. This technique can reduce the settling time by more than 87.5% in comparison with the conventional switching scheme. Furthermore, a novel reset‐free regenerative comparator is unveiled in this paper. The proposed comparator is armed to amplify its inputs both during the reset and evaluation phases. In comparison with a conventional single‐ended comparator, the proposed comparator can reduce power consumption above 90% for the almost same input‐referred offset voltage. The proposed scheme is designed with a resolution of 8‐bit and a sampling rate of 90 MS/s in a standard 65‐nm CMOS technology. The simulation results certify that the ADC dissipates 363‐μW power with a 1.2‐V supply voltage and achieves a 7.13 effective number of bits (ENOBs), yielding a 28.8 fJ/conversion step Nyquist rate Walden FOM. [ABSTRACT FROM AUTHOR]

The highlight of in vivo or ex vivo measurement to monitor the pH value from blood or saliva is emerging in these years since changes in pH suggest that hidden diseases are about to occur. In this paper, we design and implement a SoC for pH measurement, and a dual offset cancelation technique in comparator featured with 150‐uV input referred voltage and 1‐GHz comparison bandwidth is verified. The SoC by utilizing proposed dual offset cancelation technique can sense 8 femto farad capacitance change in the deionized water, 12 femto farad change in the glucose liquid, and 14 femto farad in the 0.5% hydrochloric acid. The SoC for pH measurement is not only used to detect pH change in blood or saliva, but can also extend to wearable device to monitor human's biomarkers such as pH and Na+ in sweat to prevent the disease in advance. [ABSTRACT FROM AUTHOR]