1. LM2904WDT Substitution Conclusion Direct substitution is not feasible. The core distinction between the LM2904WDT and the original part lies in its amplifier type: it employs a "standard" bipolar input stage, as opposed to a J-FET input. This results in critical electrical performance differences. Its input bias current (20 nA) is nearly three orders of magnitude higher than the J-FET input's 30 pA of the original part. In circuits highly sensitive to input current, such as high-impedance sensor signal conditioning or integrators, this will introduce non-negligible error or DC drift. Furthermore, its slew rate (0.6V/µs) is significantly lower than the original's 3.5V/µs. When processing rapidly changing signals, its large-signal bandwidth and transient response capability will be markedly degraded, potentially causing output waveform distortion. Although its operational voltage range extends to a lower minimum, the aforementioned discrepancies render it unsuitable for applications requiring J-FET input characteristics and a higher slew rate.