A Wideband Low-Noise Linear LiDAR Analog Front-End Achieving 1.6 GHz Bandwidth, $\boldsymbol{2.7}\ \mathbf{pA}/\mathbf{Hz}^{\boldsymbol{0.5}}$ Input Referred Noise, and 103 $\mathbf{dB}\mathbf{\Omega}$ Transimpedance Gain

Linear LiDAR can obtain distance by measuring time of flight (TOF), which is widely used in unmanned, geomorphic mapping and other fields. In recent years, the demand of long-distance LiDAR is getting increased. The maximum detection range of pulsed LiDAR is mainly dictated by the signal-to-noise ratio (SNR) [1]. Fig. 1 (top) indicates that improving the SNR relies on enhancing the peak emission power of the laser pulse and reducing the noise of the analog front-end (AFE) circuit. Moreover, to comply with safety regulations for eye-safe laser energy [1], narrow high-power laser pulse is required. Since the pulse width of high-power laser has already reached sub-nanosecond range [2], an AFE with a wide bandwidth of over-1 GHz and lower noise is required, thus significantly challenging the circuit design. In the AFE, the input referred noise (IRN) is mainly dominated by the transimpedance amplifier (TIA). Prior shunt-feedback TIA (SF-TIA) [3] performs well with a narrow bandwidth around 100 MHz. But it suffers from strong trade-off between IRN, gain, bandwidth and stability. Thus, the IRN is higher than 4.5 pA/Hz
^0.5
with over-200-MHz bandwidth [4], [5], indicating unsuitable for the design of low-noise TIA with over-1-GHz bandwidth and high gain. A low IRN of 2.6 pA/Hz
^0.5
was achieved by using a narrow-band TIA along with an equalizer for bandwidth enhancement (190 MHz) [6]. But this is still not sufficient for the design of over-1-GHz TIA.