A comparative analysis of parallel delta-sigma ADC architectures

Parallelism can be used to increase the conversion bandwidth of delta-sigma (ΔΣ) analog-to-digital converters (ADCs). Time-interleaved, parallel ΔΣ, and frequency-band-decomposition ADCs are three parallel architectures that are shown to be explained using the same underlying theory. This common structure is then used to explore the design tradeoffs among these architectures. It is shown that the frequency-band-decomposition ADC is insensitive to channel mismatches but it is the most complex to design. The Hadamard modulated parallel ΔΣ ADC provides the best performance (without considering nonidealities) but requires large digital filters. Finally, a randomization technique is described that can be used with parallel ΔΣ architectures to spread out the tonal energy due to channel mismatches over the frequency spectrum.