Original Part
Shunt Voltage Reference IC Adjustable 2.495V 36 VV ±0.5% 100 mA TO-92-3
Alternative Part
Shunt Voltage Reference IC Adjustable 2.5V 36 VV ±0.25% 100 mA TO-92-3
1. KA431LZTA Substitution Conclusion
From a direct drop-in replacement perspective, the KA431LZTA is a generally viable alternative. It matches the original part in all core functionalities: reference voltage (2.495V), tolerance (±0.5%), output current (100mA), and package (TO-92-3). The key differences are as follows: its cathode operating current (Ika) is 1mA, which is higher than the original's 700µA. This will lead to a slight increase in standby power consumption in circuits demanding extremely low quiescent current, though most general-purpose designs can tolerate this deviation. Additionally, the KA431LZTA specifies a typical temperature coefficient of 50ppm/°C, a parameter not documented for the original part. This provides a clear reference for temperature performance and is considered beneficial design information. Direct substitution is acceptable provided the circuit is not sensitive to the marginal increase in power draw.
2. TL1431ACZ-AP Substitution Conclusion
The TL1431ACZ-AP is not a valid drop-in replacement. While it shares the core functionality and even offers a superior voltage tolerance (±0.25%), two critical discrepancies prevent direct substitution. First, its package is TO-92-2 (three pins in an in-line configuration), which is physically incompatible with the original TO-92-3's triangular pin layout, making it impossible to fit into the same PCB footprint. Second, its nominal reference voltage is specified as 2.5V, not 2.495V. Although the tolerance bands may overlap, this difference in nominal value could introduce a systematic offset in circuits requiring precise threshold voltages, such as precision voltage detection points. This part cannot be used as a direct substitute unless the PCB layout is redesigned and the voltage accuracy is verified to meet the application's requirements.
Analysis ID: D871-5168000
Based on part parameters and for reference only. Not to be used for procurement or production.
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