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LMK04832-SEP: OSCout Phase Alignment to CLKOUT6/8

bgoose26
Prodigy 60 points
Part Number: LMK04832-SEP


When setting the OSCout pin to drive the CLKOUT6 or CLKOUT8 signals, what is the phase relationship between the clock driven on OSCout compared to CLKOUT6/CLKOUT8?  I need one more output, but it would be need to be phase-aligned to CLKOUT6/CLKOUT8.

  • 0
    TI__Mastermind 33800 points

    There will be phase error between the OSCout copy of the FB_MUX signal and the CLKOUT copy. The total path length within the device is different - from divider to CLKOUT driver is extremely close, from divider to FB_MUX to OSCout is 3-4x the distance, so I'd expect high 10s to low 100s picosecond timing difference between the outputs (constant offset dependent upon process, variable offset dependent upon temperature). The phase error is dependent on the frequency, since it's effectively a constant propagation delay offset.

    The lowest phase error will always be between two clocks in the same channel, followed by two clocks in the same clock group. If you want, I can look at the frequency plan and suggest a placement, though I make no guarantees that I can offer a perfect solution if you just have more output requirements than the LMK04832-SEP can feasibly provide. Just let me know what frequencies you need (or if that can't be shared what divide ratios you require e.g. VCO/n, VCO/4n, etc) and how many of each.