High-sensitivity photodetection sensor front-end, detecting organophosphourous compounds for food safety

A high-sensitivity, high dynamic range photodetection sensor front-end is presented, suitable for low-cost hand-held food safety systems. This sensor front-end for detecting organophosphorus (OP) compounds incorporates an on-chip deep N-well photodetector, pulse width modulation (PWM), and a folded reference. Designed in a 0.18 μm process, measurement results show an input optical power dynamic range of 71 dB, a sensitivity of 3.6nW/cm² (0.77pA), and a power consumption of 14.5 μW. OP compound detection experiments demonstrate a limit of detection (LOD) of 0.16u mol/L, comparable to that of a commercial spectrophotometer.