1. LF347M Substitution Conclusion The LF347M exhibits significant deviations from the original ADA4004-4ARZ-RL in key parameters and is not recommended as a direct substitute. The LF347M employs a J-FET input stage, offering very low input bias current (50 pA), which makes it suitable for high-impedance sensor interfaces. However, its input offset voltage (5 mV) is two orders of magnitude higher than that of the original part (40 µV), leading to substantial degradation in DC accuracy. Additionally, its gain bandwidth product (4 MHz) is only one-third that of the original part, limiting high-frequency signal processing capability. Although the LF347M provides a higher slew rate (13 V/µs) and a wider supply range (7–36 V), the core deficiencies in precision and bandwidth restrict its use to applications where offset voltage is not critical and where high speed or high input impedance is prioritized. It cannot meet the general-purpose precision amplification requirements of the original device.