1. HCPL-4562 Substitution Conclusion The HCPL-4562 is compatible with the 6N135 in terms of package type, output configuration, and maximum output voltage. However, key differences include an increased isolation voltage of 3750 Vrms (compared to the original part’s 2500 Vrms) and a reduced maximum input forward current of 12 mA (versus 25 mA for the original). Notably, the HCPL-4562 does not specify current transfer ratio (CTR) or switching time parameters. This may lead to the following issues: if the original circuit relies on the 6N135’s minimum CTR (7%) or its higher input drive capability, direct substitution could result in signal transmission failure or mismatched response speed due to insufficient CTR or limited drive current. Therefore, this substitution is only suitable for applications with relaxed CTR and speed requirements that demand higher isolation voltage. It is recommended to verify compatibility by measuring key parameters before replacement.