1. ACML-0603H-121-T Substitution Conclusion The substitution is generally feasible, though minor differences in high-frequency filtering characteristics should be noted. The ACML-0603H-121-T matches the original part exactly in all key electrical parameters (impedance of 120Ω @ 100MHz, rated current of 1.2A) and package size (0603). Its DC resistance (DCR, max 100mΩ) is superior to the original part's 130mΩ, resulting in lower DC voltage drop and thermal dissipation on the trace—a performance improvement. However, its specifications do not explicitly designate it as a "Power Line" type, and it is from a different manufacturer. This suggests its core material composition and frequency response curve may differ slightly from the original part. Impedance characteristics at very high frequencies (e.g., well above 100MHz) or under high current conditions could vary marginally. For extremely demanding power filtering applications, its filtering performance should be validated through actual testing to ensure it meets expectations.