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ISO1228: There is no parameters about how to choose RTHR value above 1k surge level in source mode

Part Number: ISO1228

 I want to design Sourcing Type Digital Inputs with ISO1228,it can  protect against surges of 1 kV/42 Ω, 

but there have no parameters above 500V surge level in the datesheet。

only can find this。 can  somebody  provide relevant parameter about this?

Rsurge =1k respond to surge 1kv from the datasheet. there only have 500Ω in source mode

  • Hello Meng,

    Thank you for your question.

    I believe that the RTHR value is not dependent in choosing the RSurge value. The RTHR value is dependent on the RILIM value. To choose the RTHR value, please look at the RILIM values in the table.

    For example, if you want RILIM of 0 ohms with a type 1 input in source mode, the RTHR would be 1500 ohms.

    Aaditya Vittal