1. MCP6L91T-E/SN Substitution Conclusion Overall, the MCP6L91T-E/SN exhibits high compatibility with the TLV2621IDR in terms of package, basic functionality (single-channel rail-to-rail output), and core AC performance (gain bandwidth product and slew rate), making it a pin-to-pin compatible and functionally viable direct substitute. However, there are significant differences in key DC precision parameters: 1) Its input offset voltage is notably higher at 1 mV, which is four times that of the TLV2621IDR's 250 µV. In applications requiring high DC precision or small-signal amplification—such as sensor bridge amplification or precision measurement—this discrepancy could introduce non-negligible system error, directly impacting output signal accuracy. 2) Its supply current is slightly higher (850 µA vs. 800 µA), resulting in marginally greater power consumption under equivalent conditions, though this is generally not a critical concern for most applications. On the other hand, the MCP6L91T-E/SN offers a wider supply voltage range (2.4 V to 6 V vs. 2.7 V to 5.5 V), providing better power supply adaptability. If the application is not sensitive to input offset voltage—for example, in AC-coupled signal processing, level shifting, or buffer circuits where absolute accuracy is not critical—and a wider supply range is prioritized, then the MCP6L91T-E/SN is a feasible alternative. Conversely, in circuits demanding high precision for DC or low-frequency signal processing, direct substitution is not recommended.