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  1. #1
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    Digital isolator SI8711CCB......diode and fet currents?

    Hi,
    We are wishing to use the SI8711CCB digital isolator.

    SI8711CCB datasheet:
    https://www.silabs.com/documents/pub...ets/Si87xx.pdf

    Page 13 of the SI8711CCB datasheet states that the maximum allowable value of the ”average output current” of the output FET is 8mA. The same page states that the maximum allowable value of the “output sink current” is 15mA.

    ……I understand the “sink current” concept here, because its an open collector output…but what does the “average output current” mean?....after all, it doesn’t “output” any current, it merely “sinks” current , because its an open collector.

    Also, page 4 of the datasheet states that the minimum diode current to turn the input diode on is 3mA. However, the same page also says that the Threshold current to turn on the diode is 1.8mA. Which of these two values is correct?

    (The SI8711CCB is the one with the internal pullup resistor available)

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    Re: Digital isolator SI8711CCB......diode and fet currents?

    Also, page 4 of the datasheet states that the minimum diode current to turn the input diode on is 3mA.
    No. It's minimum recommended current. The datasheet recommends a higher current then the specified maximal threshold.


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