A CMOS Transimpedance Amplifier for Pulsed Laser Range Finder

摘要

The pulsed laser range finding has been extensively applied in space exploration, military use and industry, due to its advantages over other methods of non-contact ranging in simplicity, non-cooperativeness of objects, long detecting range and short range acquisition time. The integration of its receiver channel will be beneficial to weight-lightening, miniaturization and mass production of the laser range finder. A transimpedance amplifier for receiver channel of pulsed range finder is designed using 0.6-um CMOS technology in this work. It consists of transimpedance pre-amplifier, R-2R resistors ladder variable attenuator and post-amplifier. A regulated cascade circuit (RGC) is used to isolate the input capacitor from input node of transimpedance pre-amplifier, reducing the bandwidth suppression caused by large input capacitor. R-2R variable attenuator is implemented for digital gain control, achieving a total gain control range of 42dB with 7 steps and 6dB per step. Simulation shows that the circuit achieves a bandwidth of 83 MHz with the presence of a 5-pF input capacitor, and a maximum transimpedance of 125.5dBQ, meeting the requirement of high-precision pulsed laser range finder.