Dear all
We Want to do a frequency up-ramp from 8750 MHz to 8770 MHz and a second down-ramp from 8770 back to 8750 MHz. The up-ramp should be triggered by a rising edge on RampPinCLK and the down ramp should be triggered by the falling edge of RampPinCLK. However the LMX2595 does not what we would expect.
Attached i share the TICS-Pro Configuration and some measurement results.
Where is the problem here?
Hi Andreas,
Found the problem, it is a GUI issue.
To fix the bug, go to
C:\ProgramData\Texas Instruments\TICS Pro\Configurations\Devices\PLL + VCO\LMX2594
Use editor to open LMX2594_RAMP.py
Ctrl+F to find main.ivalue
Change the constant in MAIN.iVALUE to 8589934591
Hi Noel
Thanks for your answer! Because I have the LMX2595 and not LMX2595 i did the change in LMX2595_RAMP.py.
This resolves one issue. The ramp looks now very nice. However it is still out of band. The pll sweeps from 8.7 GHz to 8.72 GHz but i would like to have it from 8.75 to 8.77. 
Hi Andreas,
Sorry to get back to you late. Here is the trick.
No matter if fpd = 50MHz or 100MHz. Assuming all of your ramp frequencies are between 8700MHz to 8800MHz.
First of all, in PLL page, configure the device to lock to 8700MHz. Key point here is this frequency must be an integer channel. That is, NUM = 0.
In RAMP page,
- set the Ramp Limits to the desired start/stop ramp frequencies.
- In the Automatic Ramping Mode section, set the Desired End Frequency to the amount of frequency ramp. In this case, you need 20MHz. Main purpose of this section is to calculate RAMPx_LEN and RAMPx_INC.
Now you can use the RampClk pin to toggle the output frequency between 8770M and 8790MHz.
Same approach applies to other ramp frequencies, for example, 8750M to 8770M or 8700M to 8720MHz.
