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HMC794 out phase

I'm trying to figure out the HMC794 output phase relationship with the input reference after the cycling the power supply or disable/enable the chip, the new output phase will be same?random?or a fixed shift? Hope to find an answer.




  • The HMC794 divider latches are not initialized to a known state at power on.  In divide-by 4 mode the HMC794 will randomly select either 0, 90, 180 or 270 degree phase offset.  Similarly in divide-by 3 mode 0, 120, 240 offsets are possible and divide-by 2 mode may randomly select between 0 and 180 degree phase offset.   In divide-by 1 there is no phase offset except for the small delay through the device logic

    When disabled all internal clocking stops and the divider latch state is lost.  Output phase behavior after a chip enable is similar to power-on.