1. XC6501A2717R-G Substitution Conclusion Given alignment in core electrical parameters (fixed 2.7V output, 200mA current, 6V maximum input, package, and enable control), the XC6501A2717R-G can serve as a substitute for the XC6221A2727R-G. However, three key differences must be considered: the quiescent current drops from 50µA to 20µA, which benefits standby power optimization in battery‑powered devices; the dropout voltage increases to 0.38V at 200mA (compared to 0.17V at 100mA for the original part), requiring greater input voltage margin under heavy load and making it unsuitable for applications where the input voltage is close to the output; and the PSRR decreases from 70dB to 50dB at 1kHz, reducing power‑supply noise rejection and potentially affecting noise‑sensitive precision analog circuits. Substitution is acceptable if the application is not critical about dropout voltage or noise rejection, and low quiescent current is prioritized.