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LMK00334: Can this device be used as a 3:1 PCIe Clock Mux?

Part Number: LMK00334
Other Parts Discussed in Thread: CDCI6214,

We want to know if we can use this device to select between 3 PCIe Cloc sources. 

  1. Clock Input 0 - a 100MHz differential clock signal
  2. Clock Input 1 - a 2nd 100MHz differential clock signal
  3. Crystal Input - a local 25MHz crystal/oscillator at OSCIN/OSCOUT pins. Internal PLL would multiply the crystal/oscillator frequency to get 100MHz at the output?

Is the third option possible? Essentially, we want two options for PCIe Common Clocking and then a 3rd option for PCIe Independent Reference (IR) clocking. 

Thank you

  • Hi RuggedEngie,

    LMK00334 is just a buffer, so there's no internal PLL to multiply up the 25MHz crystal/oscillator. If you could increase the oscillator frequency to 100MHz, or else multiply up your 25MHz crystal to 100MHz externally and use that output to drive OSCin, that could work. CDCI6214 could be used as the PCIe-compliant crystal multiplier, though this is probably more expensive than just using a 100MHz oscillator.

    Regards,