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Theses Doctoral

Design of custom CMOS amplifiers for nanoscale bio-interfaces

Shekar, Siddharth

The miniaturization of electronics is a technique that holds a lot of potential in improving system performance in a variety of applications. The simultaneous miniaturization of sensors into the nano-scale has provided new ways to probe biological systems. Careful co-design of these electronics and sensors can unlock measurements and experiments that would otherwise be impossible to achieve. This thesis describes the design of two such instrumentation amplifiers and shows that significant gains in temporal resolution and noise performance are possible through careful optimization.
A custom integrated amplifier is developed for improving the temporal resolution in nanopore recordings. The amplifier is designed in a commercial 0.18 μm complementary metal-oxide-semiconductor (CMOS) process. A platform is then built with the amplifier at its core that integrates glass-passivated solid-state nanopores to achieve measurement bandwidth over an order of magnitude greater than the state of the art. The use of wavelet transforms for denoising the data and further improving the signal-to-noise ratio (SNR) is then explored.
A second amplifier is designed in a 0.18 μm CMOS process for intracellular recordings from neurons. The amplifier contains all the compensation circuitry required for canceling the effects of the electrode non-idealities. Compared to equivalent commercial systems and the state of the art, the amplifier performs comparably or better while consuming orders of magnitude lower power.
These systems can inform the design of extremely miniaturized application-specific integrated amplifiers of the future.

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More About This Work

Academic Units
Electrical Engineering
Thesis Advisors
Shepard, Kenneth L.
Degree
Ph.D., Columbia University
Published Here
January 22, 2019
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