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SN74AUC1G17: Use on 24MHz clock buffer

daniel
Genius 5095 points
Part Number: SN74AUC1G17

Hi Team,

Could SN74AUC1G17 use on 24MHz clock buffer?

We want to buffer 24MHz camera clock because the clock trace is too long:

CPU 24MHz CLOCK -- 1.5m Coax cable(50ohm) -- SN74AUC1G17 -- 450mm FPC -- camera board (2inchs PCB trace to camera module.)

Please help to confirm if SN74AUC1G17 is suit on this application. Or please help to suggest other suitable part.

Thanks

  • 0
    TI__Guru* 97046 points
    Hi Daniel,
    I think you need to talk with an RF engineer -- it's unlikely that a square wave from a logic device is going to fare very well over a transmission line like that. There's nothing stopping you from trying, but I can tell you right now that at 1.5m, you have a high chance of seeing very significant problems. For starters, the capacitance of a 50 ohm transmission line is pretty high (RG58 is 100pF/m, so 150pF for this setup). Also, you will see transmission line effects due to the line length that will add ringing and group delay. If the line is terminated properly (at 50 ohms) then the DC current will be too much for the logic gate to handle, and if it isn't (terminated at high impedance, for example), the reflections will be really bad.

    I would recommend converting the signal to an analog waveform (clean 24 MHz sine wave, ac coupled) prior to transmission, then convert it back at the other end - this would ensure a clean transmission of the clock. That's quite a bit beyond the scope of support I can provide, however. Any RF engineer should be able to help you out there.