1. AD8542ARZ Substitution Conclusion In applications not reliant on extremely low supply voltage or ultra-high precision input characteristics, the AD8542ARZ can serve as a functional substitute for the MCP6402T-H/SN. Both devices share a similar core architecture (dual-channel, rail-to-rail output, 1 MHz GBW, 45 µA/channel quiescent current) and are pin‑to‑pin compatible, allowing direct replacement. The key differences are as follows: First, the AD8542ARZ has a narrower supply voltage range (2.7 V to 5.5 V) compared to the MCP6402 (1.8 V to 6 V). It cannot be used in ultra‑low‑voltage systems between 1.8 V and 2.7 V, nor is it suitable for 6 V operation. Second, the AD8542ARZ exhibits a significantly higher input offset voltage (1 mV) than the MCP6402 (800 µV), and its input bias current (4 pA) is also slightly higher. This may introduce larger absolute error and input current error when processing small DC signals, making it unsuitable for amplification or sensor interface circuits with stringent DC accuracy requirements. Third, the AD8542ARZ offers superior slew rate (0.92 V/µs) and output drive capability (30 mA) compared to the MCP6402 (0.5 V/µs, 15 mA), delivering better performance in applications requiring fast transient response or heavier load driving. In summary, if the application operates within a 2.7 V–5.5 V supply range and is not sensitive to DC precision, this substitution is viable; otherwise, it is not recommended.