This brief presents a 0.65% relative inaccuracy CMOS temperature sensor with a duty-cycle-modulated (DCM) output. It uses a BJT-based front-end to generate a proportional to absolute temperature voltage (V_{PTAT}) and a complementary to absolute temperature voltage (V_{CTAT}), which are then modulated to a digital-friendly duty-cycle output. Dynamic element matching with Kelvin connection (KC-DEM) is applied to improve the accuracy of V_{PTAT}. To enhance the robustness of the sensor, a continuous-time dynamic single-threshold hysteresis comparator with high energy efficiency is proposed. Implemented in a standard 0.13-{m} CMOS process, the sensor has an active area of 0.086 mm2 and achieves an inaccuracy of ±0.54 °C (3) from -40 °C to 125 °C.@en

This letter presents a low-power dB-linear variable gain amplifier (VGA) with a small linear-in-dB error over a wide gain tuning range. An exponential current ratio is realized in the linear-in-dB control circuit based on the subthreshold I-V characteristic. The VGA is built with subthreshold common-gate transistors as current steering, accurately replicating the exponential current ratio and forming a tunable gain. Implemented in 55-nm CMOS technology, the proposed VGA occupies a compact active area of 0.011 mm2 excluding the buffer. It achieves a linear-in-dB error of 0.4 dB over a gain tuning range of 62.4 dB, corresponding to the state-of-the-art relative error of 0.6%. The proposed design shows constant 80-MHz bandwidth with a power consumption of 0.96 mW. @en

This work presents an energy-efficient diode-based CMOS temperature sensor. It is based on the capacitively biased diode (CBD) working principle and can operate with a 1-V supply voltage. Instead of using a separate CBD front-end and ADC, a new architecture is proposed in which the CBD front-end is directly embedded into the 1st stage of a 1-bit 2nd-order switched-capacitor ΣΔ-ADC, thereby improving both energy efficiency and accuracy. The circuit was fabricated in a standard 55-nm CMOS process and occupies an active area of 0.021 mm2. The measured inaccuracy is ±0.6 °C (3σ) from -55 °C to 125 °C after a 1-point calibration. Furthermore, it consumes 2.2 μW and achieves a resolution of 15 mK in a conversion time of 6.4 ms, which corresponds to a competitive resolution FoM of 3.2 pJ·K2@en