线性碲镉汞APD的高速焦平面读出电路研究

Research on High-Speed FPA ROIC of Line-Mode HgCdTe APD

摘要:

设计了一款线性模式碲镉汞APD的高速成像读出电路。像元内采用跨阻增益可调的电阻反馈跨导放大器（Resistance Transimpedance Amplifier，RTIA），实现了光电流的实时线性转换，利用电容补偿法对RTIA的相位裕度进行优化，解决了低增益下的输出振荡现象，结果显示，像元内RTIA跨阻增益可调范围达108~140dB，增益带宽积可达1014数量级，像元电路输出延时低于1.8ns。设计了像素外的飞行时间（ToF）测量电路，采用两段式时间数字转换器（TDC）分别进行飞行时间的大范围粗量化和高精度细量化，测量范围可达1530m，测量精度为106.5cm，线性度高于99.99%。

Abstract:

A high-speed imaging readout circuit for a linear-mode HgCdTe APD was proposed.A resistive feedback transimpedance amplifier (RTIA) with adjustable transimpedance gain is used in the image element to realize the real-time linear conversion of photocurrent, and the phase margin of RTIA is optimized by using the capacitive compensation method to solve the output oscillation phenomenon at low gain, and the results show that the RTIA transimpedance gain within the image element is 100~140dB, the GBW can be up to 1014 order of magnitude, and the output delay of the image circuit is lower than 1.6ns. A column-level time-of-flight (ToF) measurement circuit is designed, and a two-stage time-to-digital converter (TDC) is used for the wide-area coarse quantization of the time-of-flight and the high-precision fine quantization, respectively, and the measurement range can be up to 1530m, with the measurement accuracy of 106.5cm, and the linearity is higher than 99.99%.