A Wideband and High Output Swing Analog Frontend Circuit for FMCW LiDAR

Abstract

This paper proposes a low input impedance, high output swing column-level analog front-end (AFE) circuit for the frequency modulation continuous wave (FMCW) LiDAR. The AFE circuit adopts a shunt-feedback transimpedance amplifier (TIA) and an output swing compensation limiting amplifier (LA) to amplify the weak echo signal and realize the high output swing. The input direct current cancellation (IDCC) circuit is used to stabilize the output direct operating point, where the lag network is used to extend the frequency range of high gain, and the noise of the direct current is reduced by means of noise transfer. The proposed AFE circuit is implemented in a 55nm CMOS process, and the post-layout simulation results show that the circuit achieves a gain of more than 118.7 dBΩand an output swing of higher than 840 mV in the frequency range of 26 MHz∼400 MHz. The input-referred noise current is 12.45 pA/Hz <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">0.5</sup> and the power consumption is 7 mW with a 1.2 V power supply.