A 7.3 mW 200 MHz-BW 4-element Passive-Beamforming Continuous-Time ΔΣ ADC with >30dB Spatial Interferer Suppression

This paper proposes a novel BF-ΔΣM concept, which integrates passive vector modulators within the ΔΣM loop filter to suppress spatial blockers and hence greatly reduce the dynamic range requirements of the ADC. To enhance phased-array receiver performance, a CT-ΔΣM with embedded R-2R based vector modulators as feed-in coefficients is proposed. Resistive vector modulators can provide accurate phase shifting and amplitude scaling, enabling beam-steering and null-steering. This 4-element 40 nm CMOS BF-ΔΣM achieves >30 dB suppression of interferers up to three spatial interferers, 200MHz-bandwidth and >70 dB spatial blocker DR with only 7.3 mW. The BF-ΔΣM obtains 7fJ/cs and 177 dB BF-ADC equivalent Walden FoM and Schreier FoM.