Search

This paper presents a dual-mode, multi-bit, second-order oversampling ADC, which can be configured into Sigma-Delta (SD) mode or Incremental (I) mode for interfacing a single or multiple sensors in multi-sensor platforms for automotive applications. Implemented in a 130-nm CMOS technology, the proposed ADC uses only 0.4 µm devices and operates at 2.5-V supply in order to be connected to high-voltage sensors, at the cost of intrinsic lower efficiency. The device achieves a maximum SNDR of 63.0 dB and 56.4 dB in the two modes, respectively, with a bandwidth of 2.1 MHz. By reducing the bandwidth to 1.25 MHz in SD-mode a SNR of 73.2 dB is achieved. In both operating modes, the ADC is clocked at 80 MHz, consuming 2.6 mA.

This paper presents a sensor and its readout circuit suitable for contact-less temperature measurements. The sensor, designed employing a MEMS technology provided by STMicroelectronics, consists of a miniaturized micromachined silicon thermopile with 180-V/W responsivity, 540- $\text{k}\Omega $ output resistance, and 0.64-mm2 active absorbing area. The interface circuit, fabricated in a standard 130-nm CMOS process, employs chopper technique in order to provide amplification of the sensor output signal, which behaves substantially as a DC while minimizing offset and noise contributions at low frequency. Given the sensor characteristics, a single-ended architecture was preferred over the most straightforward fully-differential approach. The interface circuit reduces the offset by a factor 255, achieving an input referred offset standard deviation equal to 1.365 $\mu \text{V}$ , measured across 29 samples. The thermopile sensor and the interface circuit, integrated in two separate test-chips, were characterized and extensively measured both as stand-alone devices and together as a system to perform contact-less temperature measurements. Adding a metal cap to the thermopile sensor in order to reduce the environmental noise, a measurement accuracy of approximately ±0.2 °C was obtained, thus verifying the system suitability for human body temperature detection.

In this paper, we present a monolithic microsystem, which can perform bioimpedance analysis and electroimpedance tomography measurements as well as record electrocardiogram signals. In contrast to a full analog lock-in approach, a mixed analog/digital solution is adopted. The proposed solution has been designed, implemented, and tested using a commercial 0.35-μm CMOS technology. The tuning range of the signal generator and the detector is from 10 kHz to 10 MHz in 1 kHz steps. The circuit ensures a CMRR of 81 dB@10 kHz, which increases to 84 dB@10 MHz. The measured equivalent input noise power spectral density is en = 2.57 nV/√Hz at 10 kHz in the worst case, close to the 1/f corner frequency. It decreases until en = 1.8 nV/√Hz at 1 MHz and en = 1.9 nV/√Hz at 10 MHz. Measurements of a reference RC network performed with the proposed monolithic solution and compared with a Keysight E4980A Precision LCR Meter shows a maximal relative error of 0.8% over the whole operating frequency range.

Custom integrated DC-DC converters are frequently used to power system-on-chip architectures for achieving high-quality voltage regulation at the best possible efficiency. However, high-level models of such converters are usually incompatible with analog simulators and require the designer to re-assemble the circuit in the final design environment to verify the design with real transistor models. This process is both time consuming and error-prone. This paper presents a library of parameterizable, high-level macro-models for DC-DC converters, consisting of custom Verilog-A modules and cells from the standard libraries. The macro-models are compatible with analog simulators and offer a significant amount of flexibility to the designer.

HERMES-TP/SP (High Energy Rapid Modular Ensemble of Satellites Technologic and Scientific Pathfinder) is a constellation of six 3U nano-satellites hosting simple but innovative X-ray detectors, characterized by a large energy band and excellent temporal resolution, and thus optimized for the monitoring of Cosmic High Energy transients such as Gamma Ray Bursts and the electromagnetic counterparts of Gravitational Wave Events, and for the determination of their positions. The projects are funded by the Italian Ministry of University and Research and by the Italian Space Agency, and by the European Union Horizon 2020 Research and Innovation Program under Grant Agreement No. 821896. HERMES-TP/SP is an in-orbit demonstration, that should be tested starting from 2022. It is intrinsically a modular experiment that can be naturally expanded to provide a global, sensitive all sky monitor for high-energy transients., Comment: 15 pages, 3 figures, Proceedings of SPIE Astronomical Telescopes and Instrumentation 2020

We present the design of a multichip Application Specific Integrated Circuit (ASIC), named ORION, for the front-end readout of the X-Gamma Imaging Spectrometer (XGIS) on-board the Transient High Energy Sky and Early Universe Surveyor (THESEUS) space mission. The XGIS instrument is composed by two cameras that operate as a wide field deep sky monitors with a broad energy range from 2 keV to 20 MeV, and it is based on a position sensitive double-detection mechanism for image reconstruction, in which a single pixel is constituted by a Thallium activated Cesium Iodide (CsI(Tl)) scintillator crystals and two Silicon Drift Detectors (SDDs) glued at both crystal ends, whose signal is collected, reconstructed and digitized by the presented ORION chipset. In each camera, the ORION chipset is organized in a constellation of 12 800 analog front-end chips (ORION-FE), closely connected to the SDD anodes, and 800 mixed signal multi-channel back-end chips (ORION-BE) for signal processing and digitalization, for a total 25 600 ORION-FE and 1600 ORION-BE in the complete instrument. The back-end chips have two parallelized X and Gamma signal processors, for low-energy and high-energy photons respectively, which allow a tailored optimization on the noise and energy range requirements for each type of event. The chipset has an input dynamic range of 32 fC that allows to process signals with a linearity error below ±1.2% on the Gamma processor, and below ±0.1% on the X processor. The nominal Equivalent Noise Charge (ENC) of the system at -20 °C for an estimated detector leakage current of 0.7 pA is 12.5 el. r.m.s at 1 µs peaking time for the X processor, and 32.9 el. r.m.s. at 3 µs peaking time for the Gamma processor. The simulated power consumption is of 1.55 mW per pixel.

This article presents a fully analog, signal-to-noise-ratio-based voice-activity detection (VAD) circuit. The circuit is based on an energy-efficient analog implementation with continuous-time nonlinear operation and fully passive switched-capacitor signal processing. The overall chain is composed of a programmable-gain amplifier, a squarer, an integrator, an SC-based signal averaging circuit, and a periodic threshold update circuit for adaptability. This implementation allows the minimization of both power consumption and chip area. The VAD circuit prototype has been fabricated in a 180-nm CMOS technology and occupies an area of 0.14 mm2. The device achieves 99.5% classification accuracy in a domestic environment in the presence of loud ambient noise, consuming 760 nW from a 1.2-V supply.

The ORION chipset, a full-custom multi-chip readout and processing electronics for the X-γ Imaging Spectrometer (XGIS) on-board the THESEUS space mission, is presented. The XGIS detection plane is arranged in a matrix of 10×10 detection modules, each one composed by 64 CsI(Tl) scintillation bars (4.5 mm×4.5 mm×30 mm) optically coupled at the top and bottom ends to two 8×8 monolithic Silicon Drift Detector matrices. The top SDD, exposed to the X-ray entrance window, performs the double function of low-energy X-ray detection as well as scintillator’s readout, together with the bottom SDD, providing a detection and spectroscopic energy range from 2 keV up to 20 MeV. The need to achieve a high energy resolution, as well as a high sensitive area on the detection plane, led to the development of a chipset organized to have a minimum-area analog readout chip placed in close proximity of the SDD (ORION-FE) and a mixed-signal back-end (ORION-BE) placed a few centimeters further on the back-end board for the additional signal processing and digitization. The multi-chip readout electronics integrates two dedicated analog processors for low-energy photons up to 30 keV (X-processor) and high-energy photons up to 5 MeV (γ-processor), allowing a spectroscopy-grade resolution in the 4 decades energy band (2 keV–20 MeV) of the XGIS, with a simulated power consumption of 1.55 mW/pixel. The ORION prototype was bonded to two ~25mm2 SDDs, and extensively characterized in terms of pulse shaping, pulse discrimination and stretching functionality, as well as linearity, dynamic range and spectroscopic resolution. An optimum Equivalent Noise Charge (ENC) at –20°C of 24.3 el. r.m.s. on the X-channel (212 eV FWHM on Si), and 39.6 el. r.m.s. on the γ-channel (3.7 keV FWHM on CsI(Tl)) has been recorded.

The HERMES-TP/SP (High Energy Rapid Modular Ensemble of Satellites -- Technologic and Scientific Pathfinder) is an in-orbit demonstration of the so-called distributed astronomy concept. Conceived as a mini-constellation of six 3U nano-satellites hosting a new miniaturized detector, HERMES-TP/SP aims at the detection and accurate localisation of bright high-energy transients such as Gamma-Ray Bursts. The large energy band, the excellent temporal resolution and the wide field of view that characterize the detectors of the constellation represent the key features for the next generation high-energy all-sky monitor with good localisation capabilities that will play a pivotal role in the future of Multi-messenger Astronomy. In this work, we will describe in detail the temporal techniques that allow the localisation of bright transient events taking advantage of their almost simultaneous observation by spatially spaced detectors. Moreover, we will quantitatively discuss the all-sky monitor capabilities of the HERMES Pathfinder as well as its achievable accuracies on the localisation of the detected Gamma-Ray Bursts., 19 pages, 13 figures, Proceedings of SPIE Astronomical Telescopes and Instrumentation 2020

This paper presents a detailed analysis of an effective method to improve the linearity and, consequently, the temperature insensitivity of the output characteristic of current processing based bandgap references. The described technique is shown to be successful on a circuit which generates a temperature-invariant current of approximately 1 µA which has been designed and extensively simulated in a standard 130-nm CMOS process in the -40°C to 125°C temperature range. The circuit nominal supply voltage is 1.5 V and it has a total power consumption of about 5 µW. The analyzed linearity boosting technique, applied to the proposed circuit, provides a temperature sensitivity of the output current as low as 1.7 ppm/°C in the considered range, making it suitable for a lot of different precision applications that require a highly stable current signal with respect to temperature.

This paper presents the front-end section of the X-/γ-ray detection instrument of the HERMES mission, whose goal is to observe and localize γ-ray bursts, through a constellation of more than one hundred nano-satellites. Considering the severe volume and power consumption constraints of the nano-satellites, in the HERMES X-/γ-ray detection instrument, silicon drift detectors are read out through a mixed-signal ASIC chipset, called LYRA, based on a peculiar architecture. In particular, a small front-end ASIC (LYRA-FE), placed close to each silicon drift detector, is connected, through a current-mode link, to a multi-channel back-end ASIC (LYRA-BE). The LYRA ASIC chipset, implemented in a 0.35µm CMOS technology, achieves less than $22{\text{e}}_{{\text{rms}}}^ - $ of equivalent noise charge, with a power consumption lower than 600µW/channel from a 3.3V power supply. Thanks to the current-mode link between the LYRA-FE and the LYRA-BE ASICs, no significant crosstalk among channels can be observed, in spite of the length of the interconnection wires as large as 12cm.