A Simultaneous Multiband Continuous-Time ΔΣ ADC With 90-MHz Aggregate Bandwidth in 40-nm CMOS

Abstract

This letter presents a new class of ΔΣ modulator that combines any set of traditional NTF shapes in a single modulator. The prototype multiband ΔΣ modulator (MB-ΔΣM) demonstrates two simultaneous bands—one baseband and one bandpass. These two bands are separated by 500 MHz, have an aggregate bandwidth of 90 MHz, with up to 55-dB measured SNDR. In addition to reducing the number of ADCs, this new approach promises further system-level power savings by simplifying the RF frontend. The system-level power savings from requiring fewer analog mixers, LNAs, filters, and ADC drivers can be even more than the ADC power reduction.