A 0.3-mW/Ch 1.25 V Piezo-Resistance Digital ROIC for Liquid-Dispensing MEMS

A low-power multichannel CMOS digital read-out IC (ROIC) for differential piezo-resistive sensing is presented as part of the positioning system of a liquid dispensing MEMS. New very low-voltage and single-battery compatible CMOS circuits are proposed for digital gain tuning, pre-amplification, and integrating A/D conversion. Overall low-power consumption is achieved by operating the key devices in subthreshold in order to prevent from heating the fluidic MEMS. A complete quad-channel ROIC has been integrated in 0.35- $\mu{\hbox {m}}$ CMOS 2-polySi 4-metal technology. The reported experimental results agree with the electrical simulations.