Design and electrochemical measurement of a current-mode analog-to-time converter with short-pulse output capability using local intra-cell activation for high-speed time-domain biosensor array

摘要

This study demonstrates a current-mode analogto- time converter (CMATC) enabling short-pulse output capability by using the newly-proposed local intra-cell activation technique, which contributes to the development of high-speed time-domain biosensor array. In the conventional CMATC, the activation pulse is generated globally at the periphery. This limits the output pulse width because of the considerable parasitic word-line capacitance. In this study, a shorter pulse output was achieved by generating the activation pulse locally by using intra-cell configuration without being affected by word-line capacitances. In 1024 x 1024 configuration, 77% pulse width reduction was confirmed using SPICE simulation. A test chip was fabricated using a 0.6 mu m standard CMOS process. The measurement results obtained using a sensor chip demonstrate the expected input-output characteristic and 3.36 ns pulse output. Finally, we measure the change in potential with respect to the ratio of the ion concentration, by using Fe(CN)(6)(3-) and Fe(CN)(6)(4-) as the oxidant and reductant, respectively.