20.5 A Sub-pA ΔΣ Current Amplifier for Single-Molecule Nanosensors

Abstract

This paper presents a circuit approach based on a current-mode DeltaSigma converter having a noise floor below 150 fA <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">rms</sub> at 1kHz and at room temperature. The main advantages of this approach are that: 1) it offers a digital output that can be easily multiplexed for nanoarrays; 2) the noise floor and bandwidth trade-off is easily set by using oversampling ratios; and 3) it implements a correlated-double- sampling (CDS) scheme to reduce the 1/f noise.