A512x256CMOS Readout Circuit For IRFPA

Infrared imaging system based on infrared focal plane array (IRFPA) detectorsare widely used in the field of aerospace and industrial control. Readout integratedcircuit (ROIC) is the core of the device of the infrared focal plane, and itsperformance will affect the performance of the system of the entire infrared focalplane.Based on0.35μm2P4M CMOS process, a size of512×256, the unit size is30μm×60μm， infrared focal plane array detector front end readout circuit isdesigned.The circuit mainly consists of the front end readout cell (capacitivetransimpedance amplifier, CTIA), row charge transferring amplifier, sample-and-holdcircuit and output buffer. The paper describes in detail the timing of digital controldesign of the circuit and the working of every contained circuit, and the simulationresults are given. According to the system requirements, the design of a small area,low power consumption of the CTIA readout unit structure is used. Based on theanalysis of parasitic parameters, charge transfer is used in row readout. A12MHz/25pF output buffer amplifier design is completed. On the basis, the overallcircuit layout design and post-simulation is completed.The taped-out chip was tested.The test results show the circuit has a good response for photocurrent signals, theintegrated time and integrated capacitance can be adjusted by signals given outside ofthe chip. Output signal rate could be more than255fps. Digital noise is seriousimpact on the circuit, the possible reasons and noise suppression method is discussedin this paper.