1. Substitution Conclusion for AP2171SG-13 The AP2171SG-13 demonstrates high substitution feasibility, as it matches the original AP2161SG-13 in all core electrical specifications, package, protection features, and characteristics. The sole critical technical difference lies in the input logic: the AP2161SG-13 features an inverting input, while the AP2171SG-13 is non-inverting. Consequently, if the same Enable (EN) signal logic is maintained during replacement, the switch's ON/OFF state will be inverted. To achieve a direct drop-in replacement, the logic level of the preceding control circuit (e.g., a GPIO) must be inverted, or a hardware modification (such as reconfiguring pull-up/pull-down resistors) is required to adapt to the new control logic. Failure to do so will result in system malfunction.