A wireless FM multi-channel microsystem for biomedical neural recording applications

This paper presents a four-channel wireless microsystem, suitable for a variety of biomedical neural recording applications. The neural recording circuitry features onchip AC amplification, DC rejection, clock generation, time-division-multiplexing, and frequency modulation with RF carrier frequency tunable in the 88-108 MHz commercial FM band. A wide-band FM radio followed by a LabView-based system is utilized for demodulation and de-multiplexing to re-construct the original input data. This system consists of a 2.2 mm/spl times/2.2 mm integrated circuit and four off-chip components (1 inductor and 3 capacitors) that are wire bonded to the chip. It measures 1.8/spl times/1.3/spl times/0.16 cm/sup 3/, weighs 1.1 g including two 1.5 V batteries, and dissipates less than 2.5 mW from a 3 V power supply. The chip is fabricated using AMI 1.5 /spl mu/m double-poly double-metal n-well CMOS process. Benchtop tests show complete functionality of the wireless microsystem in both ambient light and dark conditions.

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