1. AD823AARZ-R7 Substitution Conclusion The AD823AARZ-R7 is not a direct replacement for the LT1881IS8TRPBF. It can only be considered a conditional substitute in high-speed, high-input-impedance applications where DC precision and power consumption are not critical. While both op-amps are package-compatible and share a similar supply voltage range, their core performance characteristics differ significantly. The AD823AARZ-R7 features J-FET inputs, offering an extremely low input bias current (1.3 pA)—far superior to the original part's 150 pA. This results in minimal input current error when interfacing with high-impedance sources like sensors. However, its input offset voltage (800 µV) is more than an order of magnitude higher than the original's 30 µV. This will inevitably degrade absolute accuracy in DC amplification or precision measurement circuits. Furthermore, the AD823AARZ-R7 provides substantially higher bandwidth (10 MHz GBW) and slew rate (35 V/µs) compared to the original (850 kHz, 0.4 V/µs), making it suitable for high-speed signal processing. The trade-off is a roughly 7x increase in quiescent current (6.3 mA per channel), which is unfavorable for battery-powered devices. Its output drive capability (17 mA) is also weaker than the original's 40 mA. Any substitution decision must be based on a comprehensive re-evaluation of the system's speed, accuracy, power, and drive requirements.