1. LM324DR2G Substitution Conclusion For general low-frequency applications such as sensor conditioning, voltage comparators, and filters, the LM324DR2G can serve as a direct replacement for the LM324D. This is due to their identical core architecture, package (14-SOIC), and fundamental characteristics, including wide supply voltage range and rail-to-rail output capability. The key differences are as follows: The LM324DR2G exhibits a significantly higher input bias current (90 nA) compared to the original part (20 nA). This may introduce a larger input error voltage in applications involving high-impedance signal sources. Furthermore, its gain bandwidth product (1 MHz) is slightly lower than that of the original part (1.2 MHz). Notably, a critical parameter—the slew rate—is not explicitly specified for the LM324DR2G. Collectively, these factors suggest its performance may be slightly inferior or uncertain when handling high-frequency signals or fast transients. Therefore, substitution is acceptable in DC or low-frequency circuits where input error and bandwidth/slew rate requirements are not stringent. For applications involving high precision or moderately high-speed signals, careful validation is necessary.