The LMK61E07 features fine and coarse frequency margining capabilities which allow it to be used in applications requiring the output frequency to be adjusted on the fly. In fractional PLL mode, the numerator of the PLL fractional feedback divider can be updated over I²C to update the output frequency without glitches or spikes, allowing the device to be used as a DCXO. The output frequency step size for every bit change in the numerator of the PLL fractional feedback divider is given in Configuring the PLL. The Application Curves section below illustrates the glitch-less switch in output frequency when the numerator is updated. The frequency margining features can also aid the hardware designer during the system debug and validation phase.