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TCA9617A: used in MDIO interface

Chi Zhang2
Intellectual 1690 points
Part Number: TCA9617A
Other Parts Discussed in Thread: TCA39306, PCA9306, TCA9406

Hi, Expert

my customer want to use TCA9617 as a level shifter between MAC and PHY, interface is MDIO, could it support MDIO?

BR

Chi

  • 0
    TI__Genius 15345 points

    Chi,

    What speed are you running your MDIO signal at. Typically MDIO speeds are much faster than I2C speeds and most likely the TCA9617 would not be able to achieve that speed.

    We have a device called the PCA9306/TCA39306 which does support MDIO but under specific conditions. What voltages levels are you trying to translate between, and do you need a buffer?

    Best,

    Chris

  • 0 in reply to Chris Ayoub
    TI__Intellectual 1690 points

    Hi, Chris

    thanks for your feedback.

    my customer want 1.8V-3.3V 2.5MHz MDIO signal, so we will choose PCA9306 device.

    also, I have take your https://e2e.ti.com/support/interface/f/138/t/584378 as reference.

    BR

    Chi

  • +1 in reply to Chi Zhang2
    TI__Genius 15345 points

    Chi,

    That is good to hear let me know how it goes. One thing to look out for is what high level you will be able to achieve with your clock speed. You will have to balance high VOLs with slow rise time. With a speed this fast you will have to use strong pull ups in order to have fast rise times but this will hurt your VOLs.

    Another device that can work out here at a speed of 2.5MHz can also be the TCA9406. This device comes with a rise time accelerator and it's own internal pull ups. You can attach additional external pull up resistors. This device can achieve 2 Mbps with open drain driving and 21 Mbps for push pull driving. But this assumes a low capacitive load and an output impedance of your external driver of 50 ohms. This device was not tested with MDIO like the PCA9306 but it can potentially work and might be something else to look at.

    Best,

    Chris