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Mux Switch which can be used for both PCIe Interface and UART

SRC
Prodigy 240 points
Other Parts Discussed in Thread: TMUXHS4212, TMUX1136, TMUX1575

Hi,

In our custom application, we want to implement a design as shown below:

We want a Mux switch to switch between the PCIe Gen 2.0 Interface and 3.3V UART Interface (or 1.8V UART) between our processor and mPCIe slot. 

Do we have any Mux switch which can suite our requirement and tested for PCIe Gen2.0 Interface?

  • 0
    TI__Guru*** 126610 points

    Sorry, HSDC don't have such mux. I forward this ticket to other BU to see if they have it.

  • 0
    TI__Mastermind 28218 points

    Hello,

    If i'm understanding, you're only looking for mux/demux - 2 which will take the tx/rx of either UART or PCIe at your A port and then pass it through either UART (C port) or PCIe (B port) TX/RX. The max voltage will be 3.3V. What frequencies are you seeing at the TX/RX lines? 

    Thanks
    Rami

  • 0 in reply to Rami Mooti1
    Prodigy 240 points

    Hi Rami,

    Basically we are looking for Mux which can be used for both  Mux/Demux-1 and Mux/Demux-2 shown below in the updated diagram.

    If we consider TMUXHS4212 (for example), the maximum Recommended Voltage of High-speed signal pins differential I/O pins are1.8V.  But in our case the I/O Voltage of UART is 3.3V.

    Hence we are looking for Mux/Demux which can be used to switch between:

    (i) UART (3.3V) and  PCIe Gen2.0 Data Interface. 

    (ii) UART (3.3V) and  PCIe Gen2.0 Ref Clock.  

  • 0 in reply to SRC
    TI__Mastermind 28218 points

    As long as the device selected meets the minimum requirements for the voltage and frequency you're looking for, it will work. You can look through the product search tool to help narrow down some choices as well :

    Analog Switches & Muxes - Products

    I'm not sure why the PCIe TX_P and PCIe TX_n are being routed through the mux since it looks like they'll always stay the same. Correct me if i've misunderstood that. So currently, it looks like you're looking for a 2 channel 2:1 for both of these. 
    For Mux1 the frequency looks to be 100MHz so the TMUX1136 will be a good fit. Low on resistane, low leakage, support 0V to 5V I/O, and bandwidth of 250MHz.
    What's the frequency of the PCIe TX/RX lines? I know UART doesn't tip over the low <10MHz range. If the PCIe are expected to be the same you can use the same TMUX1136.

    Another solution could be to combine mux 1 and mux 2 together in a 4 channel 2:1 mux. TMUX1575 would be a good option. Very high bandwidth, supports 0 to 3.3V. 

    Thanks,
    Rami

  • 0
    TI__Guru*** 126610 points

    TMUXHS4212 can not support UART signal.

    Regards,

    brian

  • 0 in reply to Brian Zhou
    TI__Genius 10974 points

    Hi Brian,

    As Rami suggested, the TMUX1136 or the TMUX1575 can fit this use case. No need for the TMUXHS4212 for this application.

    Let us know if you have additional questions on this!

    Thanks!

    Bryan