1. EMI0603R-68 Substitution Conclusion Direct substitution is not recommended. The primary discrepancy lies in its impedance (68Ω @100MHz), which is approximately 15% lower than the original part (80Ω @100MHz). Consequently, its noise suppression performance (insertion loss) around the target frequency of 100MHz will be significantly inferior to the original design, potentially failing to achieve the intended filtering effect. This degradation in a key electrical characteristic is the critical barrier to substitution. While it offers a higher current rating (600mA) and a lower DC resistance (100mΩ), which are beneficial for reducing voltage drop and thermal dissipation, the mismatch in the core filtering characteristic limits its use to circuits with relaxed impedance tolerance or those specifically requiring slightly lower impedance. It cannot serve as a general-purpose equivalent replacement.