Model-Based Low-Noise Readout Integrated Circuit Design for Uncooled Microbolometers

This paper presents a design model for uncooled microbolometers readout integrated circuits (ROIC). The relation between infrared focal-plane array (FPA) performance and ROIC design specification limits is shown distinctly. A simple way to find optimal operating conditions for a certain ROIC construction is also described. The signal and noise model of the ROIC is investigated in detail. A reasonable estimate of noise equivalent temperature differences for uncooled microbolometer detectors can be calculated with this model. A capacitor feedback transimpedance amplifier readout circuit is treated as an example. An experimental readout chip based on this model has been designed and implemented on silicon using a 0.5-mu m COMS technology. The temporal root mean square output noise voltage is 424 mu V, which corresponds well with the measurement result. The result demonstrates the reliable prediction of achievable improvements for FPA by using this model.