1. XC6221C2727R-G Substitution Conclusion From a core functionality perspective, the XC6221C2727R-G matches the original part in key electrical parameters (e.g., maximum input voltage, output voltage, output current, dropout voltage, PSRR) and package. However, a critical difference precludes a direct drop-in replacement: the active logic level of its Enable (EN) pin is inverted relative to the original. The XC6217D series features an active-low EN pin (disabled when EN=Low), whereas the XC6221C series uses an active-high EN pin (enabled when EN=High). A direct substitution would completely disrupt the system's power-on/off control logic, potentially causing failure to start up or an inability to power down. Additionally, its quiescent current (Iq) increases from 8µA to 50µA, which negatively impacts ultra-low-power applications such as battery-powered systems. Direct substitution is not feasible. It could only be considered if the external circuitry is redesigned (e.g., modifying the EN pin's pull-up/pull-down configuration) to accommodate the new logic level, and the higher standby power consumption is acceptable.