1. AP2191SG-13 Substitution Conclusion The AP2191SG-13 can be considered as a potential substitute, but key technical differences require careful evaluation. The primary change is the switch from an N-channel to a P-channel MOSFET. This alters the gate drive logic, which may not be fully compatible with the original design; the control circuit's logic level matching must be verified. Its maximum output current (1.5A) is higher than the original part's (1A), providing greater current margin. However, its typical on-resistance (95mΩ) is also significantly higher than the original part's (70mΩ). Consequently, under the same load current, the AP2191SG-13 will exhibit a higher conduction voltage drop and power dissipation, potentially leading to more severe heating. On a positive note, its newly added reverse current protection is a beneficial addition for applications such as USB ports. The package is compatible, allowing for a direct footprint replacement.