A new architecture for neural signal amplification in implantable brain machine interfaces

This paper reports a new architecture for variable gain-bandwidth amplification of neural signals to be used in implantable multi-channel recording systems. The two most critical requirements in such a front-end circuit are low power consumption and chip area, especially as number of channels increases. The presented architecture employs a single super-performing amplifier, with tunable gain and bandwidth, combined with several low-key preamplifiers and multiplexors for multi-channel recordings. This is in contrast to using copies of high performing amplifier for each channel as is typically reported in earlier literature. The resulting circuits consume lower power and require smaller area as compared to existing designs. Designed in 0.5 µmCMOS, the 8-channel prototype can simultaneously record Local Field Potentials and neural spikes, with an effective power consumption of 3.5 µW per channel and net core area of 0.407 mm(2).