LMX2572EVM: In manual ramping, limitation of output freqyency.

Tool/software:

Hello,

We would like to use the manual ramping mode of the LMX2572.

For example, we would like to do a ramp between 2.86 and 2.88GHz using LMX2572EVM board and the TICS-Pro software.

You can see how we configure the PLL on TICS-Pro on the following pictures :


As you can see we define the VCO output limits high and low to 5760 MHZ (2 * 2.88GHz) and 5720 MHz (2 * 2.86GHz).

When we try to make several steps (RAMP0 active) the output frequency can't go further than 2.8689GHz (VCO frequency : 5737,8MHz). We Don't understand why. Do you have an idea of what can be the problem ?

Thanks.

Regards,

Malo