High-precision low-power DNA readout interface chip for multichannel nanopore applications

This paper presents a high-precision and low-power DNA readout interface chip (RIC) for multichannel nanopore applications. A current-to-voltage (I/V) converter, comprising a resistive-feedback transimpedance amplifier (rf-TIA) and a difference amplifier (diff-amp), is typically used as a DNA RIC to detect minute ionic currents through a nanopore channel. However, conventional rf-TIAs require an output buffer to drive a low resistive load raised from the diff-amp, which results in high power consumption and low area efficiency on a given chip size. This diff-amp also amplifies unwanted input offset voltage, which limits output dynamics. In this work, we replace the diff-amp with a non-inverting structure to avoid the need for an output buffer, and propose a novel offset cancellation block (OCB) to drastically reduce the deleterious offset effect. This DNA RIC is fabricated in a 0.35μm CMOS process and is demonstrated employing an α-hemolysin (α-HL) protein nanopore and 40-mer single-stranded DNA (ssDNA) molecules.