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LMX2595EVM: LMX2595EVM Output Power

zaheer ahmed
Prodigy 30 points
Part Number: LMX2595EVM
Other Parts Discussed in Thread: LMX2595, USB2ANY

Hi There, I bought the LMX2595EVM to use it as an RF Synthesizer locked to an external 100MHz.  However, I can only measure -0.5dBm at the RFOutAP (RFOutAM is 50Ohms to gnd and RFOutB is left open circuited).  What setting should I use on the TICSPro GUI to yield +5dBm.

Thanks 

  • 0
    Prodigy 30 points

    an update to my original question, I measured +5dBm on ESA (2dB loss of RF Cables/Connector) but only at 5GHz.

  • 0 in reply to zaheer ahmed
    TI__Guru* 93180 points

    Hi Zaheer,

    Could you try again without using a RF cable? That is, connect the EVM directly to a test equipment.

  • 0 in reply to Noel Fung
    Prodigy 30 points

    I have already done that and noted that the max output is around 6dBm but only at 5GHz, it then decreases sharply.  At 9GHz, the output is -5dBm.  The Spec says that the LMX2595 produces +7dBm.

  • 0 in reply to zaheer ahmed
    TI__Guru* 93180 points

    Hi Zaheer,

    Here is the data of my EVM at RFoutAP, you should get similar output power from the EVM. The data in datasheet was taken with a test board having very short trace length, this board is similar to this one: https://www.ti.com/tool/LMX2594PSEVM

    5GHz  7.45dBm

    6GHz  6.64dBm

    7GHz  4.81dBm

    8GHz   4.12dBm

    9GHz   2.9dBm

    10GHz  0.69dBm

    11GHz  0.28dBm

    There is no trick in operation to get this output power. The only reason I can guess for very low output power is it could be an soldering issue. Try do a touch-up to make sure the soldering of the SMA connector, C5, C7 and C6 are good.

    Also try verify if you can get better output power at RFoutAM or RFoutB. 

  • 0 in reply to Noel Fung
    Prodigy 30 points

    Hi there, I will double check but I got similar power levels from RFOutB.  The board that I received are brand new (ordered in the last week of Dec2022), so not sure why they would have issues with the SMA connector, C5,7 and 6.  Aren't all devices being fully tested before shipment to a customer?

    Please note that my device is an LMX2595EVM with a Controller Board (USB2Any).

  • 0 in reply to zaheer ahmed
    TI__Guru* 93180 points

    Hi Zaheer,

    In production, we test the output at 100MHz to ensure the output path is through. 

    Since you get the same power at RFoutB, I tend to suspect this is not an EVM issue. Do you have other test equipment capable of measuring RF power at 9GHz?