We are using an ADRV9364-Z7020 Picozed board in an LTE test application, receive only. We're noticing that above about 3GHz RF frequency the sensitivity of the Picozed module appears to degrade significantly - perhaps by up to between 10 to 20 dB. Looking at the AD9364 datasheet I can't see any indication that this degradation is expected, and the receive balun on the board should exhibit very little variation over the entire frequency range of the AD9364. Is it correct to assume reasonably flat sensitivity performance across the receive frequency range (within 2 or 3 dB say), all other factors being equal?
As a second question, I notice that the temperature stability of the Picozed reference oscillator Y4 is specified at +/- 25ppm. This is a fairly low spec for this part, considering some of the potential applications of the AD9364, such as LTE. Why is such a part specified for the Picozed board? (Please note in our application we can use a very stable external frequency reference, so can work around the stability issue). I expect other customers may experience similar issues.