A wide dynamic range receiver channel for a pulsed time-of-flight laser radar

An integrated receiver channel for a pulsed time-of-flight (TOF) laser rangefinder has been designed and tested. The bandwidth of the receiver channel is 170 MHz, the transimpedance can be controlled in the range from 1.1 k Omega to 260 k Omega, and the input-referred noise is similar to6 pA/root Hz. The distance measurement accuracy is +/-4.7 nim, (average of 10 000 measurements), taking into account walk error (input signal amplitude varies in the range 1 : 624) and jitter. A considerable increase in the input dynamic range of the receiver has been achieved by placing an integrated current buffer with variable attenuation between the external photodetector and the transimpedance preamplifier. Integrated electronic gain control structures together with the small size and low power consumption achieved by the use of full custom integrated technology considerably simplifies rangefinding devices for many applications. The circuit was implemented in an 0.8-mum BiCMOS process.