A high-speed, low input current CMOS integrated front end for multi-spectral photodiode arrays

A low current front end trans-impedance amplifier (TIA) switching bank for multi-spectral photodiode (PD) arrays is presented. The design mitigates PD capacitance effects by using a g
_m
-boosted input common-gate stage. Simulation results show that a bandwidth of 97 MHz can be reached with a maximal gain of 7.53 MΩ with a tuning range of 24 dB. The system is suited to low PD currents as its total input referred rms current noise over a 100 MHz bandwidth is of 41 nA.