Design, experimental verification, and analysis of a 1.8-V-input-range voltage-to-current converter using source degeneration for low-noise multimodal CMOS biosensor array

摘要

A multimodal complementary metal-oxide semiconductor (CMOS) biosensor array manufactured using measurement methods such as potentiometry, amperometry, and impedimetry improves its cost competitiveness and measurement accuracy. In addition, it provides a wider range of application because it can obtain signals from multiple aspects. To develop high-signal-to-noise ratio (SNR) multimodal biosensor arrays, time-domain current integration was proposed in the literature and found to be effective. In addition to amperometry and impedimetry, it is possible to perform current integration using the potentiometry output by employing a voltage-to-current converter (VCC). However, a conventional VCC with a fixed transconductance mode does not provide a sufficient input range (<0.6 V) and its noise property has not been investigated. In this work, we investigate the design and noise property of a newly proposed VCC with source degeneration that enhances the input range. For evaluating the proposed method, a test chip was fabricated in a 0.6 mu m CMOS. The measured results successfully demonstrate that the input range was enhanced from 0.6 to 1.8V. Autonomous current limitation was also confirmed. The measured total input-referred noise was 0.445mV (from 10 Hz to 10 kHz, assuming current integration at every 1 ms). (C) 2017 The Japan Society of Applied Physics