摘要 : This article presents an adaptive zoom-capacitance-to-digital converter (CDC)-based CMOS humidity sensor. The humidity sensor is realized by means of two differential capacitors whose dielectrics are sensitive to humidity. The sen... 展开 This article presents an adaptive zoom-capacitance-to-digital converter (CDC)-based CMOS humidity sensor. The humidity sensor is realized by means of two differential capacitors whose dielectrics are sensitive to humidity. The sensing capacitors are interfaced with a zoom CDC, which consists of a successive-approximation-register (SAR) analog-to-digital converter (ADC) and a 3rd-order delta–sigma modulator (<inline-formula> <tex-math notation="LaTeX">$\Delta \Sigma \text{M}$ </tex-math></inline-formula>). The SAR ADC eliminates the influence of the baseline capacitance to reduce the input range of the <inline-formula> <tex-math notation="LaTeX">$\Delta \Sigma \text{M}$ </tex-math></inline-formula>. To improve the energy efficiency of the CDC across the full input range, a power-aware floating inverter amplifier (FIA) array is proposed, which is configured based on the conversion results of the SAR logic. In addition, an adaptive range-shift (ARS) zoom CDC is proposed to: 1) resist off-chip parasitics and interference and 2) allow low redundancy and a more energy-efficient FIA-based comparator, thus reducing power consumption. The proposed CMOS humidity sensor is implemented in a 0.11-<inline-formula> <tex-math notation="LaTeX">$\mu \text{m}$ </tex-math></inline-formula> CMOS process. Measurement results show a capacitance resolution of 17.9 aF and an effective number of bits (ENOB) of 14.0 within a conversion time of 1.01 ms. The proposed humidity sensor consumes 1.5 <inline-formula> <tex-math notation="LaTeX">$\mu \text{W}$ </tex-math></inline-formula> of power and exhibits a 0.0094 % relative humidity (RH) resolution and a ±1.5 %RH peak-to-peak accuracy (3<inline-formula> <tex-math notation="LaTeX">$\sigma $ </tex-math></inline-formula> error of 5.5 %RH) among 12 chips from 20 to 85 %RH, and it achieves a figure of merit (FoM) of 0.135 pJ<inline-formula> <tex-math notation="LaTeX">$\cdot $ </tex-math></inline-formula>%RH², which is more than six times better than the state of the art. 收起