1. RC4558DGKR Substitution Conclusion The RC4558DGKR cannot directly substitute the LM2904VDMR2G and should only be considered for replacement under specific conditions. The most critical differences are its significantly narrower operating voltage range (10-30V) compared to the original part (3-32V), rendering it non-functional in low-voltage systems such as single-supply 3.3V or 5V rails. Furthermore, its output drive capability (10mA) is substantially lower than the original's (40mA), which may lead to output distortion or failure to achieve the intended voltage swing when driving heavier loads (e.g., low-impedance loads). Although the RC4558 offers performance advantages in bandwidth (3MHz vs. 1MHz), slew rate (1.7V/µs vs. unspecified), and input offset voltage (500µV vs. 7mV), making it more suitable for precision and speed-critical applications like audio or signal conditioning circuits, the fundamental incompatibilities in voltage and current preclude its use as a general-purpose substitute. It is only applicable in scenarios where the operating voltage is confirmed to be above 10V and the load is light.