1. LM2904QDRG4 Substitution Conclusion From the perspective of basic functionality and package, the LM2904QDRG4 can serve as a substitute for the original part. However, there are notable differences in its key performance parameters that require attention. Specifically, its gain-bandwidth product (700 kHz) is lower than that of the original part (1 MHz), resulting in slightly reduced signal bandwidth or high-frequency response capability at the same gain. Additionally, its input offset voltage (3 mV) is marginally higher than the original's (2 mV), which may lead to a slight degradation in DC accuracy. On the positive side, its input bias current (20 nA) is significantly better than the original's (45 nA), making it advantageous for applications with high-impedance signal sources. Furthermore, its lower quiescent current contributes to reduced power consumption. Therefore, for general-purpose applications that are not high-frequency critical or demanding of ultimate DC precision, but could benefit from lower input current and power dissipation, this part can be considered a viable substitute.