1. LM358S-13 Substitution Conclusion Direct substitution carries a high risk and is only marginally acceptable in specific applications with low-frequency and low dynamic requirements. It is not recommended as a general-purpose replacement solution. The core difference lies in the output structure: the original part features a push-pull output capable of actively sourcing and sinking current, providing strong drive capability. In contrast, the LM358S-13 is a differential output, which is essentially an open-source output structure. Its high-level drive capability relies on an external pull-up resistor, leading to significantly degraded performance when driving loads directly or when fast rise times are required. Furthermore, the BA3404F-E2 offers a higher slew rate (1.2 V/µs) and gain-bandwidth product (1.2 MHz), providing far superior signal fidelity when handling rapidly changing or higher frequency signals compared to the LM358S-13 (typical slew rate ~0.3–0.5 V/µs, GBW = 700 kHz). Although the LM358S-13 has advantages in input bias current, quiescent power consumption, and lower operating voltage limit (3 V), the degradation in these key dynamic parameters and output drive capability may lead to failure in meeting the original design expectations after substitution—particularly in driving capacitive loads, signal response speed, or output swing.