AD9361 RX1A/RX2A RF power and input impedance difference

Hello,

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.

Thank you.

  • 0
    •  Analog Employees 
    on Jan 25, 2021 2:52 PM 1 month ago

    Are you using custom board or eval board? Was this board working previously? Looks like the board is damaged. check for any physical damage to the board

    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.

    Yes. you can do that safely without causing any damage to the chip.