1. LMH6655MA/NOPB Substitution Conclusion Direct substitution is not recommended. The critical deficiency lies in severely inadequate dynamic performance: its slew rate (200V/µs) is only about 1/7 of the original part (1400V/µs). When handling fast transitions or large signals, the LMH6655 will respond much more slowly, which may cause significant signal distortion. Additionally, its gain-bandwidth product (260MHz) is both a different parameter type and lower in value compared to the original part’s -3dB bandwidth (300MHz), indicating that its small-signal bandwidth under unity gain may not be sufficient. Furthermore, its input bias current (5µA) is more than an order of magnitude higher than the original part (400nA), which will introduce greater DC error when buffering or amplifying high-impedance signal sources. Although it offers advantages such as a wider minimum supply voltage (4.5V), lower quiescent current, and higher output current capability, these benefits do not compensate for its major shortcomings in the core specifications for high-speed applications.