Speaker
Mr
Konstantinos Makris
(ISD S.A.)
Description
We present a monolithic, very high resolution analog-to-digital converter suitable for high precision space applications. The converter is a low-noise, low sampling rate, radiation hardened device optimized to operate in a frequency range from 0.1mHz to 1kHz with nominal output sampling frequency of 6 kHz. The ADC receives a differential voltage input and outputs 24-bit word samples. A simple serial output interface is used. The converter operates on a single clock domain. System architecture is based on a
2nd order, discrete-time (switched capacitor) Sigma-Delta modulator with a
1-bit quantizer and oversampling ratio of 64 to 2048. The first integrator features Correlated Double Sampling to defeat flicker noise and perform auto-zeroing function. The modulator is followed by a decimation filter which reduces the sampling frequency by a factor of the oversampling ratio, to the nominal output sampling frequency. The Decimator consists of a 4th order SINC decimation stage with a programmable factor of up to 128 followed by four cascaded stages of Half-Band filters realizing a factor of 16. Sampling rates up to 96kHz are possible thanks to the selectable oversampling ratio. The theoretical discrete-time model exhibits a Signal-to-Quantization ratio of 141 dB, with the target SNR to be at least 113dB over the entire temperature range. The converter has been implemented in a radiation tolerant 0.15μm CMOS process of Atmel using a well established and rigorous mixed-signal design flow. The analog part has been hardened using dedicated process options, specific devices and special design rules. The digital part has been hardened using hardened standard cell libraries and triple-mode redundancy in all blocks.
Primary authors
Mr
Adel Hachemi
(ASTUS S.A.)
Dr
Antonis Dadaliaris
(ISD S.A.)
Dr
Dimosthenis Fragopoulos
(ISD S.A.)
Mr
Konstantinos Makris
(ISD S.A.)
Mr
Laurent Crespy
(ASTUS S.A.)
Mr
Makis Karaolis
(ISD S.A.)
Ms
Olga Dokianaki
(ISD S.A.)
Co-authors
Dr
Boris Glass
(ESA-ESTEC)
Dr
Constantin Papadas
(ISD S.A., ASTUS S.A.)
