A32×32CTIA Readout Circuit System Design For Infrared Focal Plane Array

As capacitive feedback transimpedance amplifier (CTIA) readout circuit is widelyused in infrared focal plane arrays (IRFPA), the paper mainly focuses on the explorativedesign of high-performance CTIA readout circuit cell and a small readout circuit array.The study, which is based on the radiation-hardened of CMOS circuit background,carries out theory analysis and design research with the readout unit circuit and arraysystem. A high-performance readout pixel circuit and the32×32array of the systemarchitecture have been designed, and the data can be accurately read out throughout thissystem.The IRFPA includes infrared detector array and readout circuit array, so firstly thepaper describes them. An equivalent physical model of the photovoltaic infrareddetector is been built to carry out the theoretical basis for readout circuit. Theadvantages and disadvantages of different CMOS readout circuit are been compared,thus the CTIA readout circuit is chosen as the research subject because of its obviousadvantages.Secondly, a high performance CTIA readout circuit should have a steady detectorbias voltage, high injection efficiency and high output signal linearity. The physicalmodel of CTIA readout circuit has been established. The designed high performancereadout circuit has an injection efficiency of98.6%, a detector bias voltage variation of0.493mV and a non-linearity of the output signal of the0.92%. To improve otherperformance index of the readout circuit, the design of the reset switch, the samplingcapacitor and the source follower are analyzed.Thirdly, the system architecture of32×32infrared focal plane readout circuit arrayis constructed. Sequential pulse generator is used to design row and column signalproducing circuit. To realize the control of the frame frequency and row frequency, therow frequency synchronizing signal HSYNC and frame frequency synchronizing signalFSYNC are used to control the enabled port. And the whole circuits are verified bysimulation.Finally, based on the standard mixed analog-digital0.5μm/5V2P3M CMOS technology, the overall32×32infrared focal plane array circuits are simulated.Analyzing the switching noise of row and column switches, the mode which has a betterreadout result is proposed as the final readout model.The simulation results show that the designed digital signal control module canvery accurately read out the data of the32×32array. The entire chip layout is givenwith the full-custom design method. DRC, LVS and parasitic extraction simulation isconducted with layout verification tool. And the chip has been successfully taped out.In this paper, the research and design of32×32infrared focal plane array circuitshave an important research significance. It provides research support for the radiationhardened CMOS circuit, and also has a certain reference value on the design of largearray readout circuits.