1. AS431BZTR-G1 Substitution Conclusion The AS431BZTR-G1 can directly replace the LM431ACZ/NOPB and offers improvements in key performance parameters, though its maximum operating voltage is slightly lower. Specifically, the AS431BZTR-G1 provides better initial accuracy (±1% vs. ±2.2%) and a lower temperature coefficient (20 ppm/°C vs. 50 ppm/°C), delivering a more precise and stable voltage reference in the same application. This makes it particularly suitable for circuits sensitive to temperature drift or requiring high accuracy. Its maximum output voltage is 36 V, which is slightly lower than the original part’s 37 V. If the original circuit operates near the 37 V limit, a reevaluation is necessary; otherwise, the AS431BZTR-G1 can be used as a drop‑in replacement in most applications below 36 V. Both devices are fully compatible in package (TO‑92‑3), cathode current (1 mA), and output current (100 mA), requiring no hardware design changes.