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ISOW7841: Confirm if Is it possible to use ISOW7841 as an ethernet insulator?

Jonathan Geronga
Expert 7930 points
Part Number: ISOW7841
Other Parts Discussed in Thread: ISO1640, ISOW7741

Hi Team,

Can the customer use this ISOW7841 as an ethernet insulator?
Please let me know so they can mass-produce their product using this chip.

Thanks,

Jonathan
 

  • 0
    TI__Mastermind 49445 points

    Hi Jonathan,

    The Ethernet port is generally isolated using magnetics near the port and hence we don't see many requests asking for Ethernet isolation. If customer still wants to further isolate these signals, then the signals in the interface between MCU and Ethernet PHY can be isolated. These signals are categorized into two sections MII/RMII and MDIO/MDC (serial management). MII / RMII signals can be isolated using unidirectional digital isolators while serial management signals being bidirectional I2C like I/Os, they require a bidirectional isolator.

    Digital isolators like ISO77xx and ISO67xx can be used to isolate MII / RMII signals while ISO1640 can support serial management pins isolation.

    If you are looking to use a digital isolator with integrated DC/DC converter then I recommend to use ISOW7741 which is a second generation device from ISOW7841. ISOW7741 offers much better emissions performance and the data channels also support 1.8V operation which might be needed for MII / RMII channels.

    Let me know if customer has any further questions on this, thanks.

    Regards,
    Koteshwar Rao

  • 0 in reply to Koteshwar Rao
    TI__Expert 7930 points

    Hi Koteshwar,

    Thank you for your support in this thread and for the great information you shared.

    The customer would like to confirm now if can he use ISOW7841 between PHY and connector, not between MCU and PHY? or is this technically possible?

    Regards,

    Jonathan

  • 0 in reply to Jonathan Geronga
    TI__Mastermind 49445 points

    Hi Jonathan,

    Thanks for sharing additional information. The Ethernet interface lines between PHY and connector use differential signalling which ISOW7841 or any other single-ended digital isolators won't be able to supports. These devices are also not capable of driving long Ethernet cables. Hence, it is not possible to use any of these isolators for Ethernet isolation between PHY and connector. I do not have any alternate devices to suggest either. Thanks.

    Regards,
    Koteshwar Rao