A 72-µW 90-dB Wide-Range Potentiostatic CMOS ΔΣ Modulator with Flicker Noise Cancellation for Smart Electrochemical Sensors

This paper presents a potentiostatic-amperometric Delta-Sigma modulator (ΔΣM) for electrochemical sensors, which reuses the electrode-electrolyte impedance for quantization noise shaping. The proposed ΔΣM is based on a second-order single-bit CT architecture and it includes a cancellation mechanism of the flicker noise coming from the feedback DAC. Rail-to-rail CMOS basic building blocks for the ΔΣM circuit implementation are presented with the aim of allowing a wide-range potentiostatic operation. Post-layout simulation results are reported for a complete 72-µW 90-dB smart electrochemical sensor frontend currently being integrated in 0.18-μm 6-metal CMOS technology.