1. LM224KADG4 Substitution Conclusion From a package compatibility perspective, the LM224KADG4 can be directly substituted. However, its technical characteristics differ significantly from the original part, limiting its feasibility as a replacement to non-critical general-purpose amplification applications. The key differences are as follows: The LM224KADG4 employs a standard bipolar input stage rather than a J-FET input. This results in a substantially higher input bias current of 15nA (30,000 times greater than the LT1465's 0.5pA) and an input offset voltage of 2mV (more than 3 times worse than 600µV). These parameters will introduce significant errors in applications involving high-impedance signal sources, precision DC amplification, or low-leakage requirements. Furthermore, its quiescent current (1.4mA per channel) is considerably higher than that of the LT1465 (145µA per channel), which may lead to thermal or battery life issues in power-sensitive designs. Although it offers slightly higher bandwidth and a wider supply voltage range (3V to 30V), the loss of core precision and low-power advantages renders it unsuitable for the high-accuracy, low-power scenarios for which the original part was intended.