Low-Noise Dual-Channel Current Amplifier for DNA Sensing with Solid-State Nanopores

A compact platform for nanopore-based detection is presented. The system is tailored for high-capacitance (hundreds of pF) solid-state nanopores with integrated tunneling electrodes for DNA detection and label-free sequencing. This platform includes two low-noise current sensing channels and auxiliary biasing and selectable filtering circuits. In order to overcome the noise/bandwidth trade-off of the standard transimpedance configuration, an improved integrator-differentiator topology is adopted. The use of a discrete couple of matched JFETs at the differential input allows achieving very low equivalent input voltage noise (1.5nV/root Hz) critical with high input capacitance. Thus, the transimpedance amplifiers provide 100M Omega gain, 75kHz bandwidth and 11pA(rms) noise, comparable with the state-of-the-art performance. The system design, its characterization and lambda-DNA detection with a sub-20nm pore are reported.