An Electrical Impedance Spectroscopy IC with a Printable, Fractal Root Textile Sensor for Perspiration Analysis.

This paper presents an electrical impedance spectroscopy (EIS) system-on-chip with a fractal root textile sensor for rapid sweat collection followed by sodium ion $(\mathrm{N}\mathrm{a}^{+})$ concentration and sweat flow rate analysis. The proposed design achieves an impedance resolution of 8.1 $\mathrm{m}\Omega/\sqrt{}\mathrm{H}\mathrm{z}$ at a sweeping frequency of up to 30 kHz and an output current of up to 100 $\mu \mathrm{A}$. The total harmonic distortion is less than 1%. The maximum detectable load impedance is 14 $\mathrm{k}\Omega$, while the total power consumption is 768 $\mu \mathrm{W}$. The proposed textile sensor and readout IC allow a $\mathrm{N}\mathrm{a}^{+}$ concentration sensitivity of 2.5 code/mM and a noise floor of The chip achieves a sensitivity of 2.5 code/mM and a noise floor of 0.476 $\mu \mathrm{M}/\sqrt{}\mathrm{H}\mathrm{z}.$