1. MCP6L91RT-E/OT Substitution Conclusion Given compatibility in basic characteristics such as package, bandwidth, and rail-to-rail output, this device can serve as a conditional, application-specific substitute rather than a perfect drop-in replacement. The key technical differences are as follows: its input bias current (1 pA) offers a five-order-of-magnitude advantage over the original part (260 nA), which significantly reduces error in applications demanding extremely high input impedance (e.g., photodiode sensing, ion measurement). Conversely, its input offset voltage (1 mV) is substantially worse than the original's 80 µV, introducing non-negligible zero error in DC precision-critical circuits (e.g., precision sensor amplification, data acquisition front ends). Furthermore, its minimum operating voltage (2.4V) is slightly higher than the original's (2.2V), which may cause compatibility issues in ultra-low-voltage systems. Substitution feasibility is highly dependent on the specific application's priority trade-off between DC accuracy and input impedance.