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A 128×128 SPAD LiDAR Sensor with Column-Parallel 25ps Resolution TA-ADCs
  • +5
  • Na Tian,
  • Zhe Wang,
  • Kai Ma,
  • Xu Yang,
  • Nan Qi,
  • Jian Liu,
  • Nanjian Wu,
  • Liyuan Liu
Na Tian
Institute of Semiconductors Chinese Academy of Sciences
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Zhe Wang
Institute of Semiconductors Chinese Academy of Sciences
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Kai Ma
Institute of Semiconductors Chinese Academy of Sciences
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Xu Yang
Institute of Semiconductors Chinese Academy of Sciences
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Nan Qi
Institute of Semiconductors Chinese Academy of Sciences
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Jian Liu
Institute of Semiconductors Chinese Academy of Sciences
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Nanjian Wu
Institute of Semiconductors Chinese Academy of Sciences
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Liyuan Liu
Institute of Semiconductors Chinese Academy of Sciences

Corresponding Author:[email protected]

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Abstract

This letter presents a design of single photon avalanche diode (SPAD) light detection and ranging (LiDAR) sensor with 128×128 pixels and 128 column-parallel time-to-analog-merged-analog-to-digital converts (TA-ADCs). Unlike the conventional TAC-based SPAD LiDAR sensor, in which the TAC and ADC are separately implemented, we proposed to merge the TAC and ADC by sharing their capacitors, thus avoiding the analog readout noise of TAC’s output buffer, improving the conversion rate, and reducing chip area. The reverse stop-start logic is employed to reduce the power of the TA-ADC. Fabricated in a 180nm CMOS process, our prototype sensor exhibits a timing resolution of 25ps, a DNL of +0.30/-0.77 LSB, an INL of +1.41/-2.20 LSB, and a total power consumption of 190mW. A flash LiDAR system based on this sensor demonstrates the function of 2D/3D imaging with 128×128 resolution, 25k inter-frame rate, and sub-centimeter ranging precision.