Based on a detailed comparative analysis, the onsemi 4N33 can serve as a replacement for the original Vishay 4N33-X001, as both devices share identical core isolation and transfer parameters. These include a 5300Vrms isolation voltage, a minimum current transfer ratio (CTR@10mA) of 500%, and equivalent switching times. The differences lie in the onsemi variant's higher output current (150mA vs. 100mA), greater maximum forward current (80mA vs. 60mA), and slightly lower typical forward voltage (1.2V vs. 1.25V). Substituting with the onsemi part may therefore provide enhanced load drive capability, wider input-side current margin, and marginally reduced input power consumption. However, it is essential to verify in the actual application whether the original circuit design is compatible with the higher output current to avoid potential overloading risks. Overall, given the parameter alignment and comparable performance, the substitution is highly feasible.