1. Substitution Conclusion for AP2161SG-13 The AP2161SG-13 aligns with the TPS2061D in basic functionality and key specifications, but a direct, drop-in replacement is not feasible without design modifications. The primary differences are as follows: the output stage changes from an N-channel to a P-channel MOSFET, altering the drive logic and structure of the power path, which necessitates a re-evaluation of the original design. The input logic shifts from non-inverting to inverting; this directly requires the host controller GPIO logic to be inverted, otherwise the switch state will be opposite. The on-resistance, Rds(On), increases from 70mΩ to 95mΩ, leading to a higher conduction voltage drop and power dissipation under the same load current, potentially impacting system efficiency and thermal design. A reverse current protection feature is added, which is a beneficial additional function for applications like USB ports, though the original design likely did not depend on it. Substitution requires board-level re-validation and potential design adjustments.