1. AD818ARZ Substitution Conclusion From a core performance and packaging perspective, the AD818ARZ can serve as a functional substitute, but it involves key technical trade-offs and is not a direct, unconditional pin-compatible replacement. The differences are as follows: The AD818ARZ's specified 130MHz bandwidth (-3dB) is lower than the LT1225's 150MHz gain-bandwidth product (GBP). Under the same closed-loop gain, the AD818ARZ may exhibit a narrower actual bandwidth and slightly weaker high-frequency signal handling capability. Its slew rate (500V/µs) is higher than that of the LT1225 (400V/µs), providing faster large-signal transient response, making it more suitable for high-speed applications like video. As a video amplifier, the AD818ARZ datasheet does not explicitly specify key DC precision parameters (such as input bias current and input offset voltage), whereas the LT1225 provides clear values (4µA, 500µV). This indicates that using the AD818ARZ in applications requiring high DC precision may introduce uncertain error risks. The substitution is suitable for video or buffer circuits where high-speed AC performance is prioritized over stringent DC accuracy requirements. However, careful verification is necessary in precision amplification, instrumentation, and other applications sensitive to offset and bias.