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We report design and measurements on a 0.13~\mum CMOS Schmitt Trigger-based quasi-digital resistance-to-frequency converter prototype that can be effectively used as a read-out circuit for nanodevice-based sensors. The readout circuit comprises an operational amplifier and an inverting Schmitt Trigger, achieving an hysteresis scaled to 1 mV-order, hence, increasing frequency compared to a standard Schmitt Trigger RC oscillator. Experimental results obtained through an opto-isolated PCB set-up show maximum 0.8% RL measurement accuracy and a dynamic range between 50~k\Omega and 3~G\Omega. The flexible R-to-F converter occupies \sim 0.005~mm^2 silicon area and has a simulated power consumption of 142~\muW at 1.2 V supply. [ABSTRACT FROM PUBLISHER]

This paper presents a very low-complexity all-digital IR-UWB transmitter that can generate pulses in the band 0–5 GHz, requiring a silicon area lower than a PAD for signal I/O. The transmitter, suited to non-standardized low data rate applications, is prototyped in a 130 nm RFCMOS technology and includes analog control signals for frequency and bandwidth tuning. Center frequency is linearly selected with voltage supply, 0.5 V for the range 0–960 MHz and 1.1 V supply for the higher 3.1–5 GHz range. The architecture is based on the same delay cell for both baseband and radio frequency signal generation and pulses fractional bandwidth remains constant when voltage supply and control voltages scale. At 420 MHz center frequency, the transmitter achieves 7 pJ/pulse, and for 4 GHz center frequency pulses, it achieves 32 pJ/pulse active energy consumption. The OOK/S-OOK transmitter occupies an area of 0.004 mm^2. For ASK modulation, the system includes a separate on-chip capacitor bank connected to the output of the transmitter for an overall size of 0.024 mm^2. For pulse rates below 100 kpps, the generated pulses meet the FCC indoor mask with an off-chip DC block capacitor. The paper also presents over-the-air measurements using a planar monopole antenna operating in the 1.5–3.7 GHz frequency range. [ABSTRACT FROM AUTHOR]