Low Power Amplifiers for Recording Activity of Electrically Active Cells

Abstract

Biological applications that require sensing individual cells have led to developments in the synthesis of large multielectrode arrays and single cell isolating microstructures. This in turn drives the need for the integration of low power electronic circuitry at or very close to the site of activity. We describe low voltage low power CMOS amplifiers that address this need by rejecting DC offsets, and have tunable bandwidths. They operate at 1.35V, with a power consumption of 37.8μW and have an input referred noise of 23μV. We also describe the design of a wireless transmission system capable of transmitting the electrical signals sensed from cells. Integration of the amplifier array with the wireless link brings continuous monitoring of neurophysiologic activity of unanesthized and freely moving animals closer to realization. The transmitter is capable of generating an ASK modulated signal at a power level of -36 dBm at a frequency of 820 MHz.