Original Part
Alternative Part
1. PS2561DL2-1Y-F3-Q-A Substitution Conclusion
Direct substitution is acceptable. The two models are identical in core isolation and output specifications, including a 5000Vrms isolation voltage, 50mA output current, 80V withstand voltage, and a 300mV saturation voltage. The only negligible difference is a slight change in forward voltage (VF) from 1.17V to 1.2V. This minor variation has an insignificant impact on the design of the current-limiting resistor in the drive circuit and the input current. It will not cause any functional or reliability issues in practical applications. This model is a performance-equivalent drop-in replacement for the original.
2. PS2561DL2-1Y-V-A Substitution Conclusion
Direct substitution is not recommended; circuit re-evaluation is required. The critical difference between this model and the original lies in the Current Transfer Ratio (CTR) range: the original specifies 100%-200% @5mA, whereas this model is rated for 50%-400% @5mA. The lower CTR minimum (50%) of this substitute may result in insufficient output current to drive the load or achieve saturation under the same input conditions, posing a risk of circuit failure. Concurrently, its higher CTR maximum indicates greater batch-to-batch variation. Although the isolation, voltage, and current ratings are the same, the significant difference in the CTR range directly impacts circuit reliability and stability. Therefore, it cannot be used as a direct replacement. A thorough re-calculation of drive capability and design margin is mandatory.
Analysis ID: D9F1-8CA1000
Based on part parameters and for reference only. Not to be used for procurement or production.
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