1. AD847JRZ-REEL7 Substitution Conclusion The AD847JRZ-REEL7 is not recommended as a direct substitute for the LT1122CS8TR due to significant differences in core characteristics, which may result in circuit performance deviating from expectations. The key distinctions are as follows: The input bias current of the AD847 (3.3 µA) is nearly three orders of magnitude higher than that of the LT1122 (12 pA). This makes the AD847 unsuitable for applications highly sensitive to input current, such as high-impedance sensor interfaces or precision integrators. Additionally, the input offset voltage of the AD847 (500 µV) is approximately four times greater than that of the LT1122 (130 µV). This introduces higher DC error and can compromise the accuracy of precision amplification circuits. While the AD847 offers advantages in speed—with a slew rate of 300 V/µs and a bandwidth of 50 MHz compared to 75 V/µs and 13 MHz for the LT1122—making it more suitable for high-speed signal processing, the two amplifiers are fundamentally designed for different applications. The LT1122 is a low-input-current, high-precision JFET-type op-amp, whereas the AD847 is a high-speed general-purpose standard type. Therefore, substitution feasibility depends on the application priorities. If the circuit is intended for high-speed AC signal processing and can tolerate compromises in input current and precision, an evaluation may be considered. However, in most cases, a circuit redesign is advisable.