1. LM258D Substitution Conclusion The LM258D is not viable as a direct substitute and can only be considered for applications with extremely low performance requirements and no concern for precision. The core discrepancies lie in its significantly lower bandwidth (1.1 MHz vs. 12.5 MHz) and slew rate (0.3 V/µs vs. 4.5 V/µs). It is completely incapable of handling mid-frequency or fast-changing signals that the original part can manage, representing a severe deficiency in dynamic performance. Furthermore, its input offset voltage is as high as 3 mV (150 times that of the original part), and its input bias current is also larger. This results in very poor DC accuracy, introducing unacceptable error in circuits requiring precision, such as sensor amplification. Although it offers lower power consumption and a partially overlapping supply voltage range, these advantages cannot compensate for the substantial gap in key performance parameters.