Bootstrapped fully differential CMOS transimpedance amplifier

This paper presents a novel bootstrapped fully differential CMOS transimpedance amplifier (BFD-TIA) for the applications of unmanned vehicle LiDAR systems. In particular, the mirrored-cascode input stage is proposed to create a fully differential input configuration, which consists of a cascode input stage and its mirrored differential stage by passing the inverted output at the drain node of the common-source transistor over to the gate of the mirrored differential stage through an AC-coupling capacitor. Also, bootstrapping technique is exploited to reduce the direct effect of the notorious photodiode capacitance upon the bandwidth and noise performance in a typical voltage-mode TIA. Test chips of the proposed BFD-TIA were implemented by using a 0.13-μm CMOS technology. Measured results demonstrate 86-dBΩ transimpedance gain, 500-Mb/s operation speed for a 0.5-pF photodiode capacitance, 7.5-pA/sqrt(Hz) average noise current spectral density, and 24-mW power consumption from a single 1.2-V supply. Chip core occupies the area of 0.022 mm².