1. SFH6326-X001 Substitution Conclusion The SFH6326-X001 can serve as a direct substitute for the HCPL-4534-020E, offering equivalent or superior performance. Specifically, the SFH6326-X001 provides a higher isolation voltage (5300Vrms vs. 5000Vrms), resulting in enhanced electrical insulation safety. Its higher minimum Current Transfer Ratio (CTR) (19% vs. 15%) ensures more reliable output transistor turn-on under identical input conditions. The device features a slightly shorter turn-off time (500ns vs. 600ns), which can contribute to marginally improved switching speed. A lower forward voltage (1.33V vs. 1.5V) helps reduce power dissipation on the input side. Furthermore, its higher maximum output voltage rating (25V vs. 20V) offers greater design headroom for the output circuit. Both parts are identical in core specifications such as channel count, package, and input/output current ratings. Therefore, the substitution is viable, and the improvements in most key parameters present no adverse effects on system performance.