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UCC21520-Q1: safety limit value

Part Number: UCC21520-Q1

Dear team,

1. In below spec, input limit is 50mW. Does this limit come primarily from the ESD diode of the input pin?

2. If an application exceeds this limit and causes the chip to fail, will it cause the insulation between primary side and secondary side of the chip to fail?

Thanks & Best Regards,


  • Hi Sherry,

    Thank you for using E2E. The 50mW limit comes from multiplying the safety current (Is) by the maximum input voltage(VI). Please also note that the safety supply power and current should not be exceeded and they vary with ambient temperature(TA). You can see the effects of this in page 11 of the same datasheet.

    Safe insulation is suitable only within the safety ratings. So exceeding the safety limits will create potential damage to the isolation barrier upon failure of the chip.