Toward 1024-Channel Parallel Neural Recording: Modular Delta-Delta Sigma Analog Front-End Architecture with 4.84fJ/C-s.mm(2) Energy-Area Product

We report an energy- and area-efficient modular analog front-end (AFE) architecture incorporating Delta-modulated Delta Sigma (Delta-Delta Sigma) signal acquisition for 1,024-channel brain activity monitoring platforms. The AFE employs spectrum-equalizing and continuous-time (CT)-Delta Sigma 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.mm(2), the smallest ever reported. The fabricated circuits consume 0.05mm(2) and 3.05 mu W/channel, exhibiting 63.8dB SNDR, 3.02 NEF, and 4.56NEF(2)V(DD).