This paper presents a high-uniformity post-CMOS fabricated uncooled microbolometer focal plane array (MFPA) integrated with an active matrix circuit. The active matrix circuit selects the row and column of MFPA, calibrates output offset and gain, and converts the resistance changes of MFPA to the output currents. The active matrix circuit with column-wise transistor-sharing scheme is proposed to improve the output non-uniformity. The output non-uniformity with proposed scheme is reduced to 26 %, compared to the conventional scheme.
Abstract-This paper presents a capacitive readout circuit for tri-axes microaccelerometer with sub-fF offset calibration capability. A charge sensitive amplifier (CSA) with correlated double sampling (CDS) and digital to equivalent capacitance converter (DECC) is proposed. The DECC is implemented using 10-bit DAC, charge transfer switches, and a chargestoring capacitor. The DECC circuit can realize the equivalent capacitance of sub-fF range with a smaller area and higher accuracy than previous offset cancelling circuit using series-connected capacitor arrays. The readout circuit and MEMS sensing element are integrated in a single package. The supply voltage and the current consumption of analog blocks are 3.3 V and 230 µA, respectively. The sensitivities of tri-axes are measured to be 3.87 mg/LSB, 3.87 mg/LSB and 3.90 mg/LSB, respectively. The offset calibration which is controlled by 10-bit DECC has a resolution of 12.4 LSB per step with high linearity. The noise levels of tri-axes are 349 µg/√Hz, 341 µg/√Hz and 411 µg/√Hz, respectively.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.