What’s the Difference Between Continuous-Time and Discrete-Time Sigma-Delta ADCs? (Download)
Sigma-delta analog-to-digital converters (ADCs) can effortlessly achieve an effective number of bits (ENOB) of 24 bits or higher, making them exceptionally suitable for the precision measurement of micro-signals. These converters are widely utilized in applications such as electronic scales, pressure gauges, industrial temperature sensors (e.g., resistance temperature detectors/thermocouples), high-fidelity audio recording and playback, and physiological signal monitoring (e.g., ECG, EEG).
Compared to successive-approximation-register (SAR) or pipeline ADCs, traditional sigma-delta ADCs trade speed for precision by necessitating oversampling and averaging, which limits the output data rates. However, the advent of continuous-time (CT) sigma-delta ADCs has enabled output rates to escalate from hundreds of samples per second to the mega-sample range, significantly broadening their application scope. This article digs into the architecture of CT sigma-delta ADCs and provides a comparative analysis with discrete-time (DT) variants.
