A 16-channel low-noise programmable system for the recording of neural signals

The current migration from passive to active neuroprobes, the increasing density in multielectrode arrays, as well as the introduction of new materials and processes for electrode fabrication, are imposing important challenges on the implementation of optimal integrated neural recording systems. In this paper, we present the design and implementation of an integrated neural acquisition system with 16 fully-differential input channels with individual channel programmability for the recording of neural activity in in vitro and in vivo experiments. Each channel consists of ac-coupled low-power, low-noise programmable amplification (from 100 to 6000 V/V) and programmable band-pass filtering, achieving 37nV/√Hz input-referred noise density while consuming a maximum of 70 μA per channel from a single 3.3V. The ASIC was implemented in a 0.35 μm CMOS technology and has a total area of 5.6 × 4.5 mm². The system has been successfully tested in in vitro experiments, achieving simultaneous extracellular recordings of action potentials and showing satisfactory signal-to-noise ratios.