A digital-intensive, low-area, time-based ADC optimized for in-situ neural recording is fabricated in a 65nm test chip and validated with in-vivo data. The intrinsic inversely proportional gain of a beat frequency based quantizer allows recording of sub-millivolt neural signals without any sophisticated amplifiers or filters. A low-area analog-front-end (AFE) is implemented with a standard digital logic inverter transimpedance amplifier and tunable low pass and high pass filters. The test chip achieves 20.9dB SNDR for a 1mVpp input at 416Hz with a bandwidth of 4.2 kHz and consumes 52μW at 0.8V. In-vivo evoked potentials and spontaneous activity were measured directly from a mouse cerebellum without any external components, validating the efficacy of the aggressive tradeoffs. These results are achieved in an area of 0.0094mm 2 /channel, including on-chip AC coupling and filter passives, which makes this an attractive architecture for complete integration in ultra-high channel count neural recording systems.
|Original language||English (US)|
|Title of host publication||2018 IEEE Biomedical Circuits and Systems Conference, BioCAS 2018 - Proceedings|
|Publisher||Institute of Electrical and Electronics Engineers Inc.|
|State||Published - Dec 20 2018|
|Event||2018 IEEE Biomedical Circuits and Systems Conference, BioCAS 2018 - Cleveland, United States|
Duration: Oct 17 2018 → Oct 19 2018
|Name||2018 IEEE Biomedical Circuits and Systems Conference, BioCAS 2018 - Proceedings|
|Other||2018 IEEE Biomedical Circuits and Systems Conference, BioCAS 2018|
|Period||10/17/18 → 10/19/18|
Bibliographical noteFunding Information:
This research was supported in part by NSF IGERT grant DGE-1069104 and NIH grant NS 18338.
ACKNOWLEDGEMENTS: This research was supported in part by NSF IGERT grant DGE-1069104 and NIH grant NS 18338.