A 16ppm/ºC ROIC for capacitive-sensor signal-acquisition applications

This paper presents a novel high performance readout integrated circuit (ROIC) for conditioning and acquiring raw sensor signals for a frequency based converter platform. It consists of specific circuitry designed to interface capacitive sensors with high efficient frequency-to-code converters powered by an ultra-low temperature dependent voltage reference circuit. Thanks to a controlled compensation of the channel length modulation effect and the suppression of mobility dependence, this ROIC has low power consumption (26 μA) and it has a temperature dependent coefficient of only 16 ppm/^oC. This novel frequency acquisition circuitry is versatile, precise and useful for signal sensor acquisition in scalable structures, improving the monitoring system reliability and performance. This ROIC has been integrated using AMS 0.35μm technology and occupies a total area of 820μm*1210μm.