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An ultra-low power voltage reference circuit is presented, which is based on proportional (PTAT) and complementary (CTAT) to absolute temperature current generation and performs current-mode voltage reference with first-order temperature compensation. Thanks to the use of subthreshold CMOS transistors and an operational amplifier, the circuit achieves low sensitivity to power supply variations while providing low voltage capability. Measurements show that the proposed circuit provides a reference voltage of around 597 mV and correctly operates with a supply voltage ranging from 3.3 V to 1 V and temperature variations from −40 to 85 °C. The overall current consumption is below 1 μA, thus making it suitable for RF-powered and ultra-low power sensor network applications. The chip was fabricated in a standard 0.13-μm CMOS technology and occupies a core area as low as 0.02 mm 2 . [ABSTRACT FROM AUTHOR]

This paper presents a 77-GHz automotive radar receiver in a 28-nm fully depleted silicon-on-insulator CMOS technology. It exploits a mixer-first direct-conversion architecture to trade-off noise and linearity performance. The receiver is composed of a 77-GHz downconverter, a variable-gain amplifier, and a switched-capacitor low-pass filter. It adopts an effective and robust approach for leakage suppression due to the TX to RX crosstalk, which overcomes both gain and linearity limitations. The receiver draws an overall quiescent current as low as 27 mA from a 1-V supply voltage and provides an overall gain up to 75 dB with a noise figure of 8.2 dB. Despite the low supply voltage, an excellent blocker immunity of −9.5 dBm is achieved along with an output 1-dB compression point as high as −1.5 dBV. [ABSTRACT FROM AUTHOR]

This paper presents an RF-powered transceiver for wireless sensor network applications. The circuit is composed of an RF energy harvesting system, implemented by means of a threshold-compensated multistage rectifier, power management unit, and phase-locked loop (PLL)-based RF front end. Initially, the PLL in closed-loop condition locks the voltage-controlled oscillator (VCO) to a multiple of the RF input frequency and allows frequency-shift keying (FSK) data recovery. Then, the PLL feedback loop is opened and the VCO signal is used to generate the uplink carrier, thus enabling active transmission without requiring external quartz for frequency reference. This approach overcomes the reader self-jamming drawback that greatly limits the operating range of backscattering-based RF-powered devices. Moreover, uplink and downlink operations are performed by exploiting a single carrier frequency according to a half-duplex communication scheme, which results in a low-complexity and low-cost wireless solution. The circuit was fabricated in a 130-nm CMOS technology and operates with a minimum input power as low as −18.8 dBm. It supports the FSK and ASK demodulation and OOK data transmission in the industrial scientific and medical band at 915 MHz. [ABSTRACT FROM PUBLISHER]