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LMX2572EVM: LMX2572 EVM Not Giving Correct Output

Part Number: LMX2572EVM
Other Parts Discussed in Thread: LMX2594EVM, , TICSPRO-SW

I can't get the LMX2572EVM to generate desired output frequencies. (I also have an LMX2594EVM and that works fine).

I know the SPI interface is working as I can disable/enable the output. When I set the board to default settings on the GUI (VCO= 6 GHz, RFOUT_A = 3 GHz) then I do see a carrier at ~ 3.7 GHz. I don't think its locking to the input 100 MHz source (I can see the 100 MHz source on a scope). I can remove the 100 MHz external board and I still get the VCO output at 3.7 GHz. When I change the output channel divider to VCO, I expect to see a 6 GHz output, instead I see nothing.

The frequency I want to generate is 4800 MHz. Changing the output frequency to 4800 MHz gives no change to the output spectrum.

  • Hello David,

    It looks like you are using an older version of TICSPRO-SW, can you click on the Help menu -> About TICS Pro and download the latest from the web and tell me what version you are using. Please upgrade the version so that we can eliminate that from being the potential problem.

    If the problem persists I would try toggling RESET in the User Controls tab, before you load the default configuration. After loading default configuration make sure to click on the "Calibrate VCO" button.



  • I upgraded from v 1.6.8 to 1.7.2 but that made no difference. Applying the reset on the user controls tab does make the IC function correctly though.

    Thank you for the fix.