1. OPA1013DN8 Substitution Conclusion The OPA1013DN8 only partially overlaps with the original part in terms of wide supply voltage range, but its core performance targets different application scenarios, making it unsuitable as a direct replacement. Key differences include: its slew rate (0.35 V/µs) and gain-bandwidth product (600 kHz) are significantly lower than those of the NJM3404AD (1.2 V/µs, 1.2 MHz). This results in insufficient dynamic response when handling high-frequency or fast-changing signals, potentially causing output distortion or response lag. Although its input bias current (7 nA) and offset voltage (200 µV) are far superior to the original part, indicating higher DC accuracy, this does not compensate for its major shortcomings in AC performance. It is only suitable for applications where speed is not critical but input precision and power consumption are prioritized, and cannot cover the general-purpose medium-bandwidth applications targeted by the original design.