Original Part
1. LM431ACZX Substitution Conclusion
The LM431ACZX can functionally substitute the TL431BILPRAG, as both are adjustable shunt voltage references from onsemi, share compatible packages (TO-92-3), and match key parameters such as output current (100 mA), maximum output voltage (36 V), temperature coefficient (50 ppm/°C), and cathode current (1 mA). The differences lie in output voltage tolerance (LM431ACZX: ±2% vs. original: ±0.4%) and nominal output voltage (LM431ACZX: 2.5 V vs. original: 2.495 V). Substitution will notably reduce system voltage accuracy, with tolerance widening potentially increasing output voltage error by up to 5 times (from ±0.4% to ±2%). This makes it suitable for applications where reference voltage precision is not critical—such as non‑precision power supplies or protection circuits—but may introduce unacceptable deviation in high‑precision analog circuits or measurement systems. The trade‑off should be evaluated based on the specific application.
2. LM431BCZX Substitution Conclusion
The LM431BCZX is a closer substitute for the TL431BILPRAG, as both share the same nominal output voltage (2.495 V) and fully match parameters including package, output current, maximum voltage, and temperature coefficient. The only difference is tolerance (LM431BCZX: ±1% vs. original: ±0.4%). Substitution results in a slight reduction in output voltage accuracy, with tolerance error increasing approximately 2.5 times. This deviation has minimal impact on most general‑purpose circuits—such as voltage regulators or error amplifiers—and is generally acceptable. However, in applications demanding very high precision (e.g., precision sensor or data‑converter references), the cumulative error effect should be evaluated. Overall, the LM431BCZX can be considered a viable substitute in non‑critical precision scenarios, though system‑level performance verification prior to substitution is recommended.
Analysis ID: 4595-0F09000
Based on part parameters and for reference only. Not to be used for procurement or production.
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