Section 3.2 of the Si5317 datasheet states: "Following a power-up or reset, the overall device skew will revert to the reset value, although the input-to-output skew is
effectively random." Does this mean that the input-to-output skew will be different and unpredictable after every reset? If it reverts to the reset value, why would it be random?
The input to output skew can vary from power-up to power-up and upon reset. Once a power-up or reset occurs, register values are reloaded which will reset the divide-by circuitry with the same values, but starting the division process over, and a calibration takes place, such as setting the VCO value - events such as these will cause skew variations. Any adjustments made to the INC/DEC pins will also be lost upon power-up / reset, requiring new adjustments if skew alignment is critical to the application.