This thread has been locked.

If you have a related question, please click the "Ask a related question" button in the top right corner. The newly created question will be automatically linked to this question.

SN74AVCH2T45: Does this device support the hot-plug of SFP+ module ?

Part Number: SN74AVCH2T45
Other Parts Discussed in Thread: SN74AVC2T45

Hi All

We intend to use SN74AVCH2T45 to translate the signal of SFP+ module(such as RX RATE , TX DISABLE) from 1.8V to 3.3V , and the 3.3V side will be connected to the SFP+ . 

So , does the hot-plug of SFP+ module can cause damage to SN74AVCH2T45 ?  P.S. VCC of SN74AVCH2T45 will not power down in the whole process.

Hope for your reply

Thank you

该设备是否支持SFP+模块的热插拔

  • Hello, and welcome to the forums!

    The question of "will hot-plugging damage this device" is really a question of "what is going to happen when hot-plugging occurs?"

    I can't answer that second question easily without knowing a great deal about your system. For example, do you expect to get ESD strikes on the connector? (ie will people be touching the connector?) If so, there's a high chance of damage to the logic device.

    Is your system designed to connect ground FIRST, the VCC, and _finally_ digital I/O lines?
    What will the voltage be on any one I/O line when the connection is made?
    Assuming a line starts at the wrong voltage, we can expect there to be a transient where the SN74AVCH2T45 will have to charge the line capacitance -- thus we would need to know the load capacitance.

    If you can provide me details of what kind of signals the SN74AVCH2T45 will be subjected to, then I can give you an idea of its reliability in that situation. From the information given, I can't really help.
  • Thanks!

    I drew a diagram to indicate the relevant system . And the signals need to be translate are showed in the table from SFF-8431

    For your questions ,

    will people be touching the connector? --------- In the upper diagram , people will not touch the connector , but they will touch the module . But , the antistatic gloves are required

    Is your system designed to connect ground FIRST, the VCC, and _finally_ digital I/O lines? --------- Yes

    What will the voltage be on any one I/O line when the connection is made? -------- I did not get the point . Can the diagram above explain the problem?

    we would need to know the load capacitance --------  Sorry , I really don't know

    If your need more other info , please let me know

    Thank you!

    relevant

  • Thanks for all the information.

    I don't see any danger with hot-plugging with your system.

    I should note that the bus-hold I/O circuits will not work well with 4.7kohm pull-up or pull-down resistors. Since the bus-hold circuit provides a valid state on the line at all times, the pull-up or pull-down resistors should be removed. The other option would be to switch to a non-bus-hold version of the device such as SN74AVC2T45.