Integrated 16-channel neural recording and stimulation circuit

Here we present a low-power 16 channel neural signal measurement and stimulation system. The gain and high-pass corner frequency are programmable from 100 to 5000 and from 0.5 to 900 Hz, respectively. All channels can also be configured as outputs to electrically stimulate neurons by bipolar current pulses. The amplifying stage consists of 16 pre-amplifiers, a multiplexer and two broadband post-amplifiers. The measured signal is digitized with a 10-bit SAR A/D converter. The circuit contains a control logic for buffering the measured results and sending them into an SPI bus that is used to stream the data to a PC at 3.5 Mbps. The logic can also control the circuit’s bias currents, high-pass corner frequency, post-amplifier gains and stimulation current strengths. The mixed-signal circuit is manufactured with a low-cost 0.35 µm 4M2P IC process. The circuit consumes 1.29–1.59 mW power, depending on the amplifying gain.