Ultra-High Input Impedance, Low Noise Integrated Amplifier for Noncontact Biopotential Sensing

ABSTRACT:

Noncontact electrocardiogram/electroencephalogram/<?Pub _bookmark Command="[Quick Mark]"?>electromyogram electrodes, which operate primarily through capacitive coupling, have been extensively studied for unobtrusive physiological monitoring. Previous implementations using discrete off-the-shelf amplifiers have been encumbered by the need for manually tuned input capacitance neutralization networks and complex dc-biasing schemes. We have designed and fabricated a custom integrated noncontact sensor front-end amplifier that fully bootstraps internal and external parasitic impedances. DC stability without the need for external large valued resistances is ensured by an ac bootstrapped, low-leakage, on-chip biasing network. The amplifier achieves, without neutralization, input impedance of 60 fF$Vert$50 T$Omega$, input referred noise of 0.05 fA/$sqrt{rm Hz}$ and 200 nV/$sqrt{rm Hz}$ at 1 Hz, and power consumption of 1.5 $mu$A per channel at 3.3 V supply voltage. Stable frequency response is demonstrated below 0.05 Hz with electrode coupling capacitances as low as 0.5 pF.

Did you like this research project?

To get this research project Guidelines, Training and Code... Click Here