A Front-End ASIC for a 3-D Magnetometer for Space Applications by Using Anisotropic Magnetoresistors

This paper presents an application-specific integrated circuit (ASIC) aimed for an alternative design of a digital 3-D magnetometer for space applications, with a significant reduction in mass and volume while maintaining a high sensitivity. The proposed system uses magnetic field sensors based on anisotropic magnetoresistances and a rad-hard mixed-signal ASIC designed in a standard 0.35 μm CMOS technology. The ASIC performs sensor-signal conditioning and analogue-to-digital conversion, and handles calibration tasks, system configuration, and communication with the outside. The proposed system provides high sensitivity to low magnetic fields, down to 3 nT, while offering a small and reliable solution under extreme environmental conditions in terms of radiation and temperature.Peer reviewe

Four-channel self-compensating single-slope ADC for space environments

A multichannel high-resolution single-slope analogue-to-digital converter (SS ADC) is presented that automatically compensates for process, voltage and temperature variations, as well as for radiation effects, in order to be used in extreme environmental conditions. The design combines an efficient implementation by using a feedback loop that ensures an inherently monotonic and very accurate ramp generation, with high levels of configurability in terms of resolution and conversion rate, as well as input voltage range. The SS ADC was designed in a standard 0.35 μm CMOS technology. Experimental measurements of the performance and stability against radiation and temperature are presented to verify the proposed approach. © The Institution of Engineering and Technology 2014.Peer Reviewe

Design methodology and development of mixed-signal ASICs for space applications in standard CMOS technology

Trabajo presentado a la 21st IFIP/IEEE International Conference on Very Large Scale Integration celebrada en Estambul del 7 al 9 de octubre de 2013.-- et al.The design of mixed-signal ASICs for on-board space applications can provide several advantages that would not otherwise be possible with discrete components. However, extreme environmental conditions in terms of radiation and temperature imply a detailed knowledge of the technology used while CMOS commercial foundries do not usually have or make available these data. The aim of this work is to overcome these obstacles and offer solutions for space applications based on mixed-signal ASICs in commercial CMOS technologies. This paper presents the methodology followed for the assessment of a commercial (Austria Microsystems, AMS) 0.35 µm CMOS technology and for the development of a radiation hardened by design (RHBD) digital library. In addition, the described methodology has been applied to the development of two mixed-signal ASICs. The first chip performs the function of an optical digital transceiver for diffused-light intra-satellite optical communications. The second one implements a front-end solution for sensor data acquisition and signal conditioning and consists in a set of configurable multi-mode dual slope ADCs with resolution up to 16 bits.Peer Reviewe

An adaptive approach to on-chip CMOS ramp generation for high resolution single-slope ADCs

Trabajo presentado al ECCTD celebrado en Alemania del 8 al 12 de septiembre de 2013.-- et al.Many image sensors employ column-parallel ADCs in their readout structures. Single-slope ADCs are ideally suited for these multi-channel applications due to their simplicity, low power and small overall area. The ramp generator, shared by all the converters in the readout architecture, is a key element that has a direct effect in the transfer characteristic of single-slope ADCs. Because a digital counter is inherently present in this conversion scheme, one common practice is to use a digital-to-analog converter driven by the counter to generate the ramp. Given the direct relationship between the DAC and the ADC transfer characteristics, one of the main issues is to ensure a sufficient linearity of the DAC, with special emphasis on its monotonicity. Very often, in particular when medium to high resolutions are aimed, this requires calibration of the DAC, which must be repeated every once in a while to account for temperature, process, power supply, and aging variations. This paper presents an inherently monotonic ramp generator with high levels of linearity and stability against any expected source of variations, combined with a very efficient realization and an inherent automatic adaptability to different resolutions. The ramp generator has been designed using radiation hardening by design (RHBD) techniques, allowing its use in space applications.Peer Reviewe

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Analog-to-Digital Converte. Tecnología UMC 0.18µm 6 metalesPeer reviewe

A front-end ASIC for a 16-bit three-axis magnetometer for space applications based on anisotropic magnetoresistors

Trabajo presentado a la XXVIII Conference on Design of Circuits and Integrated Systems celebrada en San Sebastián del 27 al 29 de noviembre de 2013.-- et al.Many space applications require the measurement of magnetic fields. This includes many scientific and meteorological instruments, as well as satellite attitude control systems. The most widely used method for measuring magnetic fields in space missions has been the use of fluxgate sensors, mainly due to their reliability, robustness and relatively small mass and volume with respect to the total size of the satellite. However, the current trends of cost reduction and standardization in aerospace technology tends towards the design of small satellites, commonly called nano-satellites or even pico-satellites, embodying a new challenge in the design of low-cost space instrumentation. In this scope, fluxgate sensors are massy and large enough so that their use is not addressable for these small satellites. This paper presents an alternative design of a three-axis magnetometer for the measurement of the strength and direction of an incident magnetic field in space applications, with a significant reduction in mass and volume while maintaining a high detectivity. The proposed system uses magnetic field sensors based on anisotropic magnetoresistances (AMR) and a radiation hardened by design (RHBD) mixed-signal ASIC that performs signal conditioning and analog to digital conversion up to 16 bits, and also handles calibration tasks, system configuration and communication with the outside. The use of an ASIC instead of discrete components reduces both weight and volume, and achieves improvements in performance and consumption. The proposed magnetometer provides high sensitivy to low magnetic fields up to 30 µG of resolution while offering a small, low cost and reliable solution for space applications.Peer Reviewe

SEE characterization of the AMS 0.35 µm CMOS technology

Trabajo presentado al Radiation Effects on Components and Systems celebrado en Oxford del 23 al 27 de septiembre de 2013.This work presents experimental results for the single-event effects characterization of a commercial (Austria Microsystems) 0.35 µm CMOS technology. It improves and expands previous results. The knowledge gained is being applied in the development of a RHBD digital library.Peer Reviewe

CMOS rad-hard front-end electronics for precise sensors measurements

This paper reports a single-chip solution for the implementation of radiation-tolerant CMOS front-end electronics (FEE) for applications requiring the acquisition of base-band sensor signals. The FEE has been designed in a 0.35μm CMOS process, and implements a set of parallel conversion channels with high levels of configurability to adapt the resolution, conversion rate, as well as the dynamic input range for the required application. Each conversion channel has been designed with a fully-differential implementation of a configurable-gain instrumentation amplifier, followed by an also configurable dual-slope ADC (DS ADC) up to 16 bits. The ASIC also incorporates precise thermal monitoring, sensor conditioning and error detection functionalities to ensure proper operation in extreme environments. Experimental results confirm that the proposed topologies, in conjunction with the applied radiation-hardening techniques, are reliable enough to be used without loss in the performance in environments with an extended temperature range (between -25 and 125 °C) and a total dose beyond 300 krad