{"id":3524,"date":"2011-07-07T20:46:54","date_gmt":"2011-07-07T20:46:54","guid":{"rendered":"https:\/\/mtlsites.mit.edu\/annual_reports\/2011\/?p=3524"},"modified":"2011-07-28T15:19:51","modified_gmt":"2011-07-28T15:19:51","slug":"a-low-power-32-channel-digitally-programmable-neural-recording-system-2","status":"publish","type":"post","link":"https:\/\/mtlsites.mit.edu\/annual_reports\/2011\/a-low-power-32-channel-digitally-programmable-neural-recording-system-2\/","title":{"rendered":"A Low-power 32-channel Digitally-programmable Neural Recording System"},"content":{"rendered":"

We have designed an ultra-low-power 32-channel neural recording system in a 0.18-\u00b5m CMOS technology. The system consists of eight neural recording modules; each module contains four neural amplifiers, an analog multiplexer, an A\/D converter, and a serial programming interface. Each amplifier can be programmed to record either spikes or LFPs with a programmable gain from 49-66 dB. To minimize the total power consumption, an adaptive-biasing scheme is utilized to adjust each amplifier’s input-referred noise to suit the background noise at the recording site. The amplifier’s input-referred noise can be adjusted from 11.2 \u00b5Vrms<\/sub> (total power of 5.4 \u00b5W) down to 5.4 \u00b5Vrms<\/sub> (total power of 20 \u00b5W) in the spike recording setting. The ADC in each recording module digitizes the signal from each amplifier at 8-bit precision with a sampling rate of 31.25 kS\/s per channel and an average power consumption of 483 nW per channel. It achieves an ENOB of 7.65, resulting in a net efficiency of 77 fJ\/State, making it one of the most energy-efficient designs for neural recording applications. The presented system was successfully tested in an in-vivo<\/em> wireless recording experiment from a behaving primate with an average power dissipation per channel of 10.1 \u00b5W. The neural amplifier and the ADC occupy the areas of 0.03 mm2<\/sup> and 0.02 mm2<\/sup>, respectively, making our design simultaneously area-efficient and power-efficient.<\/p>\n\n\t\t