高性能低噪声数字读出电路

High-performance low noise digital readout circuit

红外焦平面的数字读出是信息化发展的必然方向,其关键技术是数字读出电路。介绍了数字读出电路的发展现状和主要架构,重点分析了时间噪声和空间噪声的来源和影响,并给出低噪声设计指导。同时对线性度、动态范围和帧频等主要性能进行了讨论,设计了两款数字读出电路。采用列级ADC数字读出架构设计了640×512数字焦平面探测器读出电路,读出噪声测试结果为150μV,互连中波探测器测试NETD为13 m K。基于数字像元读出架构设计了384×288数字焦平面探测器读出电路,互连长波探测器测试NETD小于4 m K,动态范围超过90 dB,帧频达到1000 Hz。所设计的两款读出电路有效提升了红外焦平面的灵敏度、动态范围和帧频等性能,表明数字读出电路技术对红外探测器性能的提升具有重要作用。

It′s the trend of information technology development that infrared focal plane array(FPA)outputs digital signal directly,the critical technique is the digital readout integrated circuit(ROIC).The architecture of digital ROIC was introduced in this paper after the summary of related research status.The sources and influence of temporal noise and spatial noise were analyzed in detail,then the design guide for low noise was also shown.In addition,two digital ROICs were designed based on the discussion of linearity,dynamic range and frame rate.The first ROIC was implemented with column-level ADCs,which was used for 640×512 digital FPA.The measurement results show that the readout noise of ROIC is 150μV,and the NETD with mid-wave infrared detectors is 13 m K.Digital pixel architecture is used for the second ROIC,which is connected to 384×288 long-wave infrared FPA.The measured NETD is less than 4 m K,and the dynamic range is larger than 90 d B.The max frame rate achieves1000 Hz.The two ROIC prototypes effectively improve the sensitivity,dynamic range and frame rate of infrared FPA,which confirms the advantages of digital ROIC technology to the performance development of infrared detectors.