1. Substitution Conclusion for AZV321KSTR-G1 Under the premise of package compatibility, identical supply current, and core architecture, the AZV321KSTR-G1 can serve as a substitute for the TSV851ICT. However, its key parameter substitution is not lossless or superior in all application scenarios. The differences and their impacts are as follows: First, regarding input characteristics, the AZV321 offers superior input offset voltage (1.7mV vs. 4mV), which is beneficial for improving DC accuracy. However, its input bias current is significantly larger (250nA vs. 27nA). This results in a more pronounced loading effect on high-impedance signal sources and may introduce greater error in applications such as photodetection or high-impedance sensor interfaces. Second, in terms of dynamic performance, the AZV321 features a higher slew rate (1V/µs vs. 0.7V/µs), enabling faster large-signal response. Conversely, its gain-bandwidth product is slightly lower (1MHz vs. 1.3MHz), which may incur a minor penalty in small-signal bandwidth. Third, regarding output drive capability, the AZV321's output current (160mA) far exceeds that of the TSV851 (70mA). This is a distinct advantage, allowing it to directly drive heavier capacitive or resistive loads. Fourth, concerning operating voltage range, the AZV321's minimum operating voltage (2.7V) is slightly higher than that of the TSV851 (2.5V). This may render it unsuitable for systems requiring extremely low supply voltages, such as those powered by a single battery cell down to 2.5V. The substitution decision should prioritize a thorough review of the application's sensitivity to input bias current and minimum operating voltage.