1. LM258AST Substitution Conclusion From a comparison of key parameters, the LM258AST as a standard dual op-amp shows similarities to the original part OPA2137E in terms of bandwidth (1.1 MHz vs. 1 MHz) and input offset voltage (1 mV vs. 1.5 mV). However, its input bias current is significantly higher at 20 nA (three orders of magnitude greater than the JFET-type’s 5 pA), its slew rate is only 0.6 V/µs (well below 3.5 V/µs), and its quiescent current is notably larger (700 µA vs. 220 µA). In applications requiring high input impedance, fast transient response, or low power consumption—such as sensor signal conditioning or high-precision integrator circuits—the LM258AST may introduce significant error or response delay. That said, its wide supply range (3–30 V) and automotive-grade qualification (AEC-Q100) make it suitable for general industrial or automotive low-frequency scenarios. If the application is not sensitive to input leakage current and slew rate, and the pinout is compatible (both in 8-MSOP packages), substitution may be considered with caution. Otherwise, it is not recommended.