1. LM258AST Substitution Conclusion Direct substitution is not recommended. The key distinction lies in the LM258AST's significantly lower gain-bandwidth product (1.1 MHz) and slew rate (0.6 V/µs) compared to the original BA4560FVM-GTR (10 MHz, 4 V/µs). The LM258AST exhibits severely inadequate capability in processing high-frequency and fast-transient signals. In applications where the original design relies on high-speed performance—such as high-speed signal conditioning or active filtering—this substitution would result in limited bandwidth and signal distortion. Although the LM258AST offers advantages including lower quiescent current, a wider minimum supply voltage (3 V), and AEC-Q100 automotive qualification, these benefits cannot offset the substantial gap in dynamic performance. Therefore, it may only be considered as a substitute in extremely low-frequency or DC applications where speed is not a requirement.