1. AP2171SG-13 Substitution Conclusion The AP2171SG-13 can serve as a potential substitute for the TPS2031DRG4 in terms of basic functionality, but key differences must be carefully evaluated. Its P‑channel output structure—compared to the original N‑channel configuration—may alter driver logic compatibility. Furthermore, its higher on‑resistance (95 mΩ vs. 33 mΩ) will increase switching losses and voltage drop, impacting efficiency under high load conditions. While the AP2171SG-13 offers a higher rated current (1 A vs. 600 mA) and adds reverse‑current protection, making it more suitable for specific applications such as USB ports, substitution requires re‑validation of thermal design and system compatibility if the original circuit relies on low on‑resistance or the N‑channel drive characteristics.