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Design of a continuous time sigma delta analog-to-digital converter for operation in extreme environments

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In this work, a high resolution analog-to-digital converter (ADC) for use in harsh environments is presented. The ADC is implemented in bulk CMOS technology and is intended for space exploration, mining and automotive applications with a range of temperature variation in excess of 250°C. A continuous time (CT) sigma delta…

In this work, a high resolution analog-to-digital converter (ADC) for use in harsh environments is presented. The ADC is implemented in bulk CMOS technology and is intended for space exploration, mining and automotive applications with a range of temperature variation in excess of 250°C. A continuous time (CT) sigma delta modulator employing a cascade of integrators with feed forward (CIFF) architecture in a single feedback loop topology is used for implementing the ADC. In order to enable operation in the intended application environments, an RC time constant tuning engine is proposed. The tuning engine is used to maintain linearity of a 10 ksps 20 bit continuous time sigma delta ADC designed for spectroscopy applications in space. The proposed circuit which is based on master slave architecture automatically selects on chip resistors to control RC time constants to an accuracy range of ±5% to ±1%. The tuning range, tuning accuracy and circuit non-idealities are analyzed theoretically. To verify the concept, an experimental chip was fabricated in JAZZ .18µm 1.8V CMOS technology. The tuning engine which occupies an area of .065mm2; consists of only an integrator, a comparator and a shift register. It can achieve a signal to noise and distortion ratio (SNDR) greater than 120dB over a ±40% tuning range.

ContributorsAnabtawi, Nijad (Author) / Barnaby, Hugh (Thesis advisor) / Vermeire, Bert (Committee member) / Gildenblat, Gennady (Committee member) / Chae, Junseok (Committee member) / Arizona State University (Publisher)

Created2011

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Design of a continuous time sigma delta analog-to-digital converter for operation in extreme environments

Partita no. 1 in B minor, BWV 1002. Double

Sonata no. 1 in G minor, BWV 1001. Presto

Brandenburg concerto, no. 4 BWV 1049. Andante

Brandenburg concerto, no. 4 BWV 1049. Presto

Fugue

Cello suite no. 2 in D minor, BWV 1008. Prelude

Cello suite no. 2 in D minor, BWV 1008. Allemande

Cello suite no. 2 in D minor, BWV 1008. Courante

Cello suite no. 2 in D minor, BWV 1008. Sarabande