An Implantable 455-Active-Electrode 52-Channel

Neural probes have become the most important tool for enabling neuroscientists to place microelectrode sensors close to individual neurons and to monitor their activity in vivo .W ith such devices, it is possible to perform acute or chronic extra- cellular recordings of electrical activity from a single neuron or from groups of neurons. After the many developments in neural implants, it has become clear that large arrays of electrodes are desirable to further investigate the activity performed by complex neural networks. Therefore, in this paper, we propose a CMOS neural probe containing 455 active electrodes in the probe shank (100 m wide, 10 mm long, and 50 m thick) and 52 simulta- neous readout channels in the probe body (2.9 3.3 mm ). In situ amplification under each electrode enables low-impedance interconnection lines, regardless of the electrode impedance, with a residual crosstalk of 44.8 dB. This design has been imple- mented in a 0.18- ms tandard CMOS technology, with additional CMOS-compatible post-processing performed at wafer level to define the electrodes and the probe outline. In this architecture, the analog front-end achieves an input-referred noise of 3.2 V and an NEF of 3.08. The power consumption of the core circuit is 949.8 W, while the total power consumption is 1.45 mW. The high-density active-electrode array in this neural probe allows for the massive recording of neural activity. In vivo measurements demonstrate successful simultaneous recordings from many indi- vidual cells. Index Terms—Active neural probe, biomedical sensor, brain-machine interface, CMOS, implantable biomedical de- vice, microelectrodes, multi-electrode arrays, neural amplifier, neural interface, neural probe, neural recording.