Toward 1024-channel parallel neural recording: Modular Δ-ΔΣ analog front-end architecture with 4.84fJ/C-s·mm2 energy-area product

We report an energy- and area-efficient modular analog front-end (AFE) architecture incorporating Δ-modulated ΔΣ (Δ-ΔΣ) signal acquisition for 1,024-channel brain activity monitoring platforms. The AFE employs spectrum-equalizing and continuous-time (CT)-ΔΣ quantization to make use of the inherent spectral characteristics of brain signals. The dynamic range (DR) of the neural signals has been compressed by 27dB (spectrum equalization). The energy-area product is the most critical figure of merit for massively-parallel recordings and the AFE achieves 4.84fJ/C-s·mm², the smallest ever reported. The fabricated circuits consume 0.05mm² and 3.05μW/channel, exhibiting 63.8dB SNDR, 3.02 NEF, and 4.56NEF²V_DD.