Relationships LO Isolation and IMD

On HMC558A's datasheet, LO to IF isolation is 45dB. But, on 12 page right side IMD table, M=0 N=1 that is LO leakage signal.

This value is the highest on the table.

I don't know why there is a difference between isolation and this value.

Thank you

The LO to IF isolation is the output IF power (at the LO frequency)  relative to the input LO power. So if the LO to IF  spec is 35 dB and the LO power is +15dBm, then the output leakage level at the IF port is -20 dBm. The spur table on page 12 of the datasheet, the output power levels are referenced to the IF output power with the RF input power at -10 dBm. So the IF output power will be around -18 dBm (insertion loss at 8GHz is -8dB approx). So by this caclulation the leaked LO singnal at the IF output (-20dBm) is 2 dB lower than the IF power of -18 dBm. This doesn't fully line up with the value in the table of -1 (-1 means that the leaked LO should be 1 dB greater than the IF power) but it is close.