HMC8191 Datasheet Spurs

Hello there,

I've been going over the HMC8191 datasheet to evaluate characteristics for a future project.

Looking at the spur tables I found some of the values to be curious.

www.analog.com/.../hmc8191.pdf

Just as an example let's look at an application: Upconversion, 6,1GHz High side LO, 18dBm, 100MHz IF.

The Spur Table on Page 38 at the Bottom left specifies these conditions (I've opted for this case since at higher Frequencies data gets sparse).

Further info/plots regarding this are on page 18 & 19.

On page 37 top left we get some info on LO harmonics at 6GHz; close enough.

Data given in the spur table is supposedly referenced to -10dBm RF output.

Positive values obviously equate attenuation.

0xIF NxLO should represent LO harmonics and are given as: -2, 10, 16, 18, 32 dBc

which equates to: -8, -20, -26, -28, -42 dBm

meaning LO isolation is about: 26, 38, 44, 46, 60 dB

Table 5 States otherwise: 37, 47, 57, 37

So ultimately there's a 10dB discrepancy in these values, if I'm not mistaken.

Similar content for 1,5GHz IF; 8,5GHz LO.

Is this because I'm misunderstanding some of the references given, could the LO used for generating this table be subpar

meaning the measured values are not actually representing mixer spurious performance or are other factors

impairing performance (see plots: Input P1dB, IP3 etc get substantially worse at 6GHz)?

Thanks in advance.