A 30.3 fA/√Hz Biosensing Current Front-End With 139 dB Cross-Scale Dynamic Range

This paper presents an 8-channel array of low-noise (30.3 fA/root Hz) current sensing front-ends with on-chip microelectrode electrochemical sensors. The analog front-end (AFE) consists of a 1(st)-order continuous-time delta-sigma (CT Delta Sigma) modulator that achieves 123 fA sensitivity over a 10 Hz bandwidth and 139 dB cross-scale dynamic range with a 2-bit programmable current reference. A digital predictor and tri-level pulse width modulated (PWM) current-steering DAC realize the equivalent performance of a multi-bit Delta Sigma in an area- and power-efficient manner. The AFE consumes 50.3 mu W and 0.11 mm(2) per readout channel. The proposed platform was used to observe protein-ligand interactions in real-time using transient induced molecular electronic spectroscopy (TIMES), a label- and immobilization-free biosensing technique.

Automated summary

This paper introduces an 8-channel array of low-noise current sensing front-ends with on-chip microelectrode electrochemical sensors, achieving high sensitivity and dynamic range while consuming low power and occupying a small area. The proposed platform was successfully applied to real-time observation of protein-ligand interactions.