1. AS431BZTR-E1 Substitution Conclusion The substitution is generally feasible, but the bias circuit requires careful evaluation and potential modification. The key differences are as follows: First, its minimum cathode operating current is 1mA, which is significantly higher than the original part’s 600µA. If the original circuit’s quiescent current is designed below 1mA, direct replacement may prevent the reference from starting or cause unstable operation. It is therefore necessary to recalculate and adjust the bias resistor to ensure the current exceeds this threshold. Second, its typical reference voltage is 2.5V (compared to 2.495V for the original). Although both fall within the ±1% tolerance, if the circuit relies on absolute accuracy rather than adjustability alone, a slight shift in system precision may occur. Third, it specifies a typical temperature coefficient of 20ppm/°C, which is a clear performance parameter and may offer an advantage over the original unspecified part in applications with significant temperature variation.