A novel low-noise wide-bandwidth transimpedance amplifier for LiDAR applications

The detection accuracy of LiDAR relies on the front-end amplification circuit employing a transimpedance amplifier (TIA). However, conventional TIA are constrained by the trade-off among noise, gain, and bandwidth, thereby limiting the achievement of high-precision detection. To address the demand of LiDAR systems for wide bandwidth and low-noise front-end amplification, this work proposes a novel TIA architecture designed for avalanche photodiode (APD)-based LiDAR applications. In particular, compared with traditional TIAs commonly used for current detection, the proposed circuit achieves significant advantages in gain tunability, noise, and bandwidth performance. Nevertheless, the non-ideal characteristics of the APD severely degrade the bandwidth of the front-end amplification circuit. To this end, this paper analyzes the performance of the proposed TIA under APD non-idealities, derives the relationship between circuit gain and bandwidth, and validates the design through LTspice simulations. The results clearly demonstrate that the proposed circuit effectively suppresses the adverse impact of APD non-idealities, and moreover achieves lower background noise and wider bandwidth at the same transimpedance gain, while maintaining gain independent of bandwidth. Therefore, the proposed design enables high-precision LiDAR detection.