One question needs your help: Where is test point of Output variance plot in figure 5 of your datasheet ADL5372? Or how is the plot obtained? Looking forward to hear from you soon.
We checked it at Modulator RFoutput(Vout, pin#13). Figure 5 shows baseband(I and Q) frequency response. We either kept baseband input level or calibrate out the variation over baseband frequency to ADL5372. And we also calibrated out RF output power variation over frequency to see how ADL5372 actually works over baseband frequency.