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LMX2581EVM: How can I simulate Loop Filter of EVM condition by PLLatinum

Part Number: LMX2581EVM
Other Parts Discussed in Thread: LMX2581

Hello Experts,

I run PLLatinum to simulate LMX2581. I tried to set EVM condition as below, but PLLatinnum returned different Loop Filter value than EVM. How did you determine loop filter for EVM? I want to get loop filter value as same as EVM by PLLatinum.
- Vin=100MHz
- Vout=2700MHz
- Fpd=20MHz
- Loop Bandwidth=27.8KHz
- Charge Pump Gain=2400uA
- VCO Frequemcy=2700MHz
* I referred User's Guide(SNAU136C), p4, "1.3 Loop Filter Values and Configuration Information" section.

Best Regards,

  • Hi Fujiwara-san,

    First of all, please use "Advanced level" to do the simulation.
    On the left hand side window, the PLL diagram, in the VCO Characteristics box, select VCO2.
    On the right hand side window, in the filer parameter box, set Gamma = 2 and T3/T1 ratio to 10% and then click Calculate Loop Filter. The filter value you will get will be very close to the EVM user's guide.