This article presents a current mode transimpedance amplifier (TIA) implemented in a standard 65-nm CMOS technology for the applications of elder-care home monitoring LiDAR sensors. Particularly, a novel mirrored current-conveyor (MCC) input configuration is proposed to lower the input impedance, thus achieving a wide bandwidth. This MCC-TIA can alleviate severe pulse spreading issue for near-range detection, enabling effective narrow-pulse recovery. Also, a feedforward control-voltage generator is newly suggested to realize an automatic gain-control within a single pulse-width duration. Measured results demonstrate the variable transimpedance gain of 5977 dB Ω to accommodate the incoming input currents of 18 μApp ∼ 2.24 mApp that corresponds to the feasible detection range of 0.55.3 meters in an elder's home. The bandwidth of 83 MHz2.6 GHz is measured with the minimum noise current spectral density of 16.8 pA/sqrt(Hz). The chip dissipates 40 mW in total, and occupies the area of 1.0 mm2, including I/O pads.
- feedforward control-voltage generator
- mirrored cascode