1. NCP431BVSNT1G Substitution Conclusion The NCP431BVSNT1G is functionally and mechanically compatible with the AZ431AN-ATRG1, but three key differences must be noted: First, its tolerance is ±0.5% (compared to ±0.4% for the original part), indicating slightly lower initial accuracy. Second, its typical temperature coefficient is 50 ppm/°C (versus 20 ppm/°C for the original part), meaning its output voltage exhibits poorer stability over temperature variations. Third, there is ambiguity in the datasheet specification for "Current – Output" (NCP lists 40 µA, while the original part specifies 100 mA); however, the actual cathode current capability for both is 100 mA. It is necessary to verify whether the operating current range meets the circuit requirements in the specific application. If the application is not sensitive to accuracy and temperature drift, and the operating current configuration aligns with the NCP431 specifications, direct substitution is acceptable. Otherwise, a reassessment of whether system performance remains acceptable is required.