Original Part
Alternative Part
1. KA431LZTA Substitution Conclusion
The KA431LZTA is a viable direct replacement. The core difference is a relaxation in initial accuracy from the original ±0.4% to ±0.5%. Consequently, the maximum potential deviation of the KA431LZTA's output reference voltage from its nominal value (2.495V) after board soldering is slightly larger by 0.1 percentage point. Considering that key parameters—including dynamic impedance, operating current range (1mA cathode current), temperature coefficient (50ppm/°C), and package (TO-92-3)—are identical, this 0.1% accuracy difference typically falls within the design margin for the vast majority of non-precision-critical applications (e.g., standard switching power supply feedback loops, voltage monitoring thresholds). It will not affect circuit functionality or reliability, allowing for interchangeable use.
2. FAN431AZXA Substitution Conclusion
The FAN431AZXA can serve as a substitute, but its applicability is limited. The primary distinction is its significantly relaxed initial accuracy of ±1%, which is 2.5 times wider than the original's ±0.4% tolerance. In the same application circuit, the FAN431AZXA introduces a larger maximum absolute error range for the provided reference voltage. This will directly degrade the system accuracy of downstream circuits relying on this reference, such as voltage divider networks or comparator thresholds. It is only suitable for applications with very lenient reference voltage accuracy requirements, high cost sensitivity, and where overall system precision is not critical (e.g., some low-cost consumer chargers or LED drivers). For any original design dependent on the ±0.4% accuracy, directly substituting the FAN431AZXA may introduce unacceptable system error and requires re-evaluation.
Analysis ID: 9411-53C2000
Based on part parameters and for reference only. Not to be used for procurement or production.
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