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This work proposes an all digital clock generator (ADCG) with a new PVT compensation technique to generate a stable and accurate frequency over wide frequency ranges up to 8GHz. To compensate frequency variations by temperature changes, a novel Zero Temperature Coefficient (ZTC) algorithm using mutual compensation between the mobility and the threshold voltage of devices has been implemented. The...
In this paper, we propose a fully integrated and area-efficient resistor-less relaxation oscillator (ROSC) for ultra-low power real-time clock (RTC) applications. The proposed ROSC is based on a conventional ROSC and modified to be area-efficient circuit configuration, without using resistors. The proposed ROSC consists of a bias current source, proportional to absolute temperature (PTAT) voltage...
This paper describes a high precision all digital on-chip oscillator. This architecture can achieve absolute precisions beyond 0.1% with only one trim. Once trimmed, the oscillator can produce any frequency within the programmable range with similar accuracy. If there are multiple oscillators on same die, trimming one oscillator will be sufficient to trim all the oscillators at multiple frequencies...
Thermal sensing is one of the most commonly desired features in IoT devices to monitor either environmental or system/chip conditions. An accurate temperature sensor usually requires carefully calibrated, high-accuracy ADCs, which prevents their use in ultra-low-power sensor nodes. In some sensing architectures, a highly accurate timing reference can replace the ADC [1]. With this in mind, we observe...
This paper presents a fully integrated RC-type relaxation oscillator with high precision over supply, temperature and process calibration by trimming, achieving 50ppm/°C maximum temperature coefficient and 1% final accuracy in the operating range. The low sensitivity to 1.8V supply is achieved by ratio metric technique and generating supply proportional voltage reference and current source. The small...
We used time-domain terahertz spectroscopy to study the dielectric properties of a KTaÜ3 crystal upon applied electric field at temperatures from 40 to 250 K. Tunable ferroelectrics are promising for the control of terahertz radiation and their study enables deeper understanding of structural instabilities close to phase transition.
Ring oscillators exhibit a strong temperature dependency. Additionally, degradation in CMOS transistors affects the performance of circuits over time and is strongly dependent on temperature during circuit operation. In order to design robust and reliable ring oscillator-based circuits, both temperature dependencies have to be considered. This work introduces systematic analyses on temperature dependencies...
High-resolution computer-controlled oscillator of 2-mm wave-range intended for the low temperature dielectrometer was designed and constructed. The proposed oscillator unit may be used as free-running source as well as phase locked source being included to the frequency synthesis system. Dependence of dielectric loss vs temperature for some diamond-like materials was measured using proposed oscillator...
We are developing hybrid-type temperature sensors using poly-Si thin-film transistors (TFTs). In this study, first, we evaluate the characteristic change of the off-leakage current of the TFT by changing the temperature several times. It is found that there is no historical effect even if the temperature changes very much. Next, we evaluate that by applying the actual driving condition. It is found...
In this paper, we present new results on the development of an original acoustic waveguides concept based on a Periodically Poled Lithium Niobate transducer. Periodically poled transducers have been investigated recently as an alternative to classical inter-digital transducers for the excitation and detection of guided acoustic waves. We expose here two different structures of RF resonators based...
Two methods are proposed to extract secret keys from ring oscillator (RO) physical unclonable functions (PUFs) under varying environmental conditions. A discrete cosine transform (DCT)-based RO PUF scheme that gives good results under nominal conditions is used in combination with these two methods, which are shown to be highly robust to environmental variations. The proposed methods significantly...
An on-chip frequency reference for built-in testing and calibration applications is presented. The design combines a proportional-to-absolute-temperature (PTAT) current reference and a relaxation oscillator core. A temperature compensation scheme is realized based on the thermal voltage, for which simulations indicate low sensitivity to process variations. The oscillator was designed and simulated...
We have evaluated temperature dependences of transistor characteristics in n-type and p-type poly-Si TFTs with and without visible light illumination. It is found that the temperature dependences of the off-leakage currents in the n-type and p-type TFTs are much larger than those of the on currents. Moreover, the temperature dependences change with visible light illumination, and the changes are different...
We have developed a hybrid-type temperature sensor using thin-film transistors generating rectangle output waveform. The advantages of the hybrid-type temperature sensor are that the large temperature dependence of the off-leakage current can be utilized, and simultaneously only a digital circuit is required to count the digital pulse. However, the conventional hybrid-type sensor has a disadvantage...
This paper presents a new time-mode duty-cycle-modulation-based high accuracy temperature sensor. Different from the well-known ΣΔADC based read-out structure, this temperature sensor's architecture utilizes a temperature-dependent oscillator to convert the temperature information into temperature related time-mode parameter, which means that the large power consumption of ΣΔADCs can be mitigated...
RC oscillator is often used in CMOS mixed-signal integrated circuits where lower power dissipation and/or lower cost are required while precision requirements for the oscillation frequency are moderate. One of the challenges in RC oscillator in CMOS integrated circuits is frequency compensation for variations of process parameters and temperature because the time constant depends on absolute values...
This paper proposes a novel integrated oscillator topology based on a transmission line. The frequency is extracted from the delay of the transmission line, which is intrinsically independent of temperature and supply variations. The architecture for the oscillator, guidelines for the design of the transmission line as well as the different building blocks are presented. The architecture is based...
A novel on-chip frequency calibration of temperature dependency is proposed for CMOS reference frequency generator. High-order temperature coefficients are rapidly extracted by employing a carefully designed on-chip heater, so that the frequency deviation due to the temperature variation is accurately estimated, and compensated in digitally by means of all-digital PLL (ADPLL). The proposed technique...
In this work, we propose a multi-resonator system capable of achieving a temperature-stable frequency output across a wide temperature range. This system utilizes three temperature-compensated MEMS oscillators whose frequency output undergoes two stages of multiplication and mixing to generate a stable clock signal. In contrast with other circuit compensation techniques, this implementation obviates...
GaAs1−xBix laser diodes (LDs) with low temperature dependence of the oscillation wavelength (dλ/dT) are demonstrated. The value dλ/dT for a GaAs0.97Bi0.03 LD was as low as 0.16 nm/K. This reduction is attributed to a reduction in the temperature coefficient of the band gap.
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