We've recently encountered an issue with the a power difference on the RX1A and RX2A channels given the same input signal. RX1A shows a lower power on the FFT than RX2A. When measuring from the trace of M1 to GND and M2 to GND, we are showing a low impedance of about 100-200 ohms. On RX2A we're shows in the 10k-100k range. We also have another board where both channels work and the measurement is also in the 10k-100k range. Couple questions:
1. Any thoughts as to how the AD9361 is having this issue?
2. Is it safe to use a multimeter to measure input impedance as we are doing as a pass/fail criteria for the AD9361? Our thought here is that we would take this measurements prior to assembly of the printed circuit board assembly. Ohmic measurements would all be unpowered.