Original Part
1. LM2904MX Substitution Conclusion
The LM2904MX can serve as a functional replacement for the RT2904WHYDT in applications where the supply voltage does not exceed 26 V and input bias current requirements are not critical. Both are dual general-purpose operational amplifiers with compatible packages (8‑SOIC), and key parameters such as bandwidth (1 MHz vs. 1.1 MHz) and input offset voltage (2 mV) are similar. However, notable differences must be considered: the LM2904MX has a lower maximum supply rating (26 V) compared to the original part (30 V), making it unsuitable if the circuit operates near the upper voltage limit. Its input bias current (45 nA) is significantly higher than that of the original (20 nA), which may increase DC error in high‑impedance signal paths. On the other hand, the LM2904MX exhibits a lower quiescent current (800 µA), beneficial for low‑power designs, and a higher output current (40 mA), providing stronger drive capability. Slew rate is not specified; bench verification is recommended to ensure dynamic performance meets system requirements.
2. LM1458M Substitution Conclusion
The LM1458M offers limited substitution feasibility, primarily due to its supply voltage constraints. It requires a single 36 V or dual ±18 V supply, which is incompatible with the original part’s wide supply range (3–30 V). This mismatch prevents operation in low‑voltage applications. Regarding other parameters: bandwidth (1 MHz) is comparable, but slew rate (0.5 V/µs) is slightly lower, input bias current (80 nA) is notably higher, and quiescent current (2.3 mA) is significantly greater, potentially leading to increased power dissipation and degraded noise performance. Although the package and output current are identical, the fundamental voltage compatibility issue restricts the LM1458M to specific high‑voltage scenarios and precludes it from being a direct drop‑in replacement.
Analysis ID: A31B-3B63000
Based on part parameters and for reference only. Not to be used for procurement or production.
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