LMK04832: Vpp AC Max Spec?

The CLKinX and OSCin inputs of LMK04832 have a triple-stacked antiparallel clamp diode group between the P and N pins. These diodes are relatively large SiGe diodes (since LMK04832 is on a BiCMOS process using SiGe wafers), so the actual threshold at which appreciable current is observed through the diodes (even at high temperature) is typically at least 2.1V between P and N pins. Additionally, the input stage is weakly biased (>10kΩ) to about 1.65V nominal common mode voltage, so if an unused leg of an input pair is capacitor-coupled to GND, the node voltage at the pin will be roughly 1.65V. The bias can vary due to process by some amount, and it can be overrided by DC-coupled inputs or by current through the clamp diodes, but generally the bias voltage level variation is small enough that only inputs exceeding the absolute maximum ratings of the device are likely to push appreciable current through the clamp diodes - this is more of a concern in the differential input use case.

The CLKinX pins have two amplifier modes: Bipolar (which uses BJT diff pair as the input stage) and MOS (which uses FET diff pair as the input stage).

The bipolar input stage is amplitude-limited in the recommended electrical conditions tables to ensure that the input amplifier remains active and not saturated - too much amplitude can cause the input stage to drop too low and turn off the input transistor, or swing too high and run out of compliance range for the current source driving the input pair. MOS input stage is less susceptible to this, and usually MOS mode is used for inputs slow enough to make the overall effect of input saturation or cutoff negligible.

Of course, MOS mode is unavailable for the OSCin input (It's a lot like CLKinX in bipolar mode), so for a VCXO use case there's not much that can be done - if the input exceeds the single-ended limits for the amplitude, you will potentially see performance degradation due to the input amplifier saturating or entering cutoff.

So, to answer your questions:

Filipe Rubinstein said:

1. Is there an absolute max for the AC coupled single input above 2.4Vpp?

Effectively no, unless you do something strange with the other input like shorting it to ground. As long as the other input is AC-coupled to its GND, the unused pin will be biased to about the mid-supply voltage, and very little current will pass through the clamp diodes until the input is greater than the damage threshold for inputs suggested in the absolute maximum ratings.

Filipe Rubinstein said:

2. Are there are any consequences for running a 2.64Vpp CMOS signal into the LMK04832? Is there any potential damage to the device for doing so?

As long as the unused pin in the input pair is AC-coupled to GND, there is no risk of using a 2.64Vpp CMOS signal with LMK04832. There might be some impact on performance, particularly as the input voltage increases. Maybe 2.64Vpp is marginal, and not worth worrying about. But if the amplitude is expected to be larger, I recommend attenuating the output to be in compliance with the recommended operating range for better performance.