1. SMDJ58A Substitution Conclusion The SMDJ58A is a viable, performance-enhanced substitute for the original SMCJ58A-TP. The key differences are its higher peak pulse current (Ipp) of 32.1A and peak pulse power of 3000W, both double that of the original part (16.1A, 1500W). Consequently, the SMDJ58A offers superior surge energy absorption. When subjected to the same standard transient overvoltage events (e.g., IEC 61000-4-5 surge tests), it provides greater clamping voltage margin and enhanced intrinsic reliability, or it can deliver safe protection in more demanding surge environments. As the critical voltage parameters (reverse stand-off voltage, breakdown voltage, clamping voltage) and package footprint are identical, this substitution is electrically and mechanically compatible. However, it should be noted that its dynamic resistance may differ slightly, which could lead to minor deviations in clamping voltage at specific current levels. This effect is typically negligible in the vast majority of applications.