1. BA2115F-E2 Substitution Conclusion Direct substitution is not recommended. The BA2115F-E2 is an audio amplifier whose key precision specifications differ from the original part by orders of magnitude: its input bias current (150nA vs. 0.2pA) is nearly a billion times higher, and its input offset voltage (1mV vs. 500µV) is 2000 times greater. This would introduce significant error and DC drift when processing microvolt-level weak signals or signals from high-impedance sources, rendering it completely unsuitable for the high-precision tasks required of the original CMOS op-amp. While it offers a wider supply range (2V-14V) and stronger output drive capability (90mA), these advantages are only relevant in audio or power-driving applications with minimal precision requirements. For precision analog circuits demanding high input impedance, low offset, and low power consumption, this substitution represents an unacceptable downgrade.